LGPL-2.1on commit tag: add tag.gpgSign config option to force all tags be GPG-signed (1c6b565)
   1
   2 While most of this project is under the GPL (see COPYING), the xdiff/
   3 library and some libc code from compat/ are licensed under the
   4 GNU LGPL, version 2.1 or (at your option) any later version and some
   5 other files are under other licenses.  Check the individual files to
   6 be sure.
   7
   8----------------------------------------
   9
  10                  GNU LESSER GENERAL PUBLIC LICENSE
  11                       Version 2.1, February 1999
  12
  13 Copyright (C) 1991, 1999 Free Software Foundation, Inc.
  14 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  15 Everyone is permitted to copy and distribute verbatim copies
  16 of this license document, but changing it is not allowed.
  17
  18[This is the first released version of the Lesser GPL.  It also counts
  19 as the successor of the GNU Library Public License, version 2, hence
  20 the version number 2.1.]
  21
  22                            Preamble
  23
  24  The licenses for most software are designed to take away your
  25freedom to share and change it.  By contrast, the GNU General Public
  26Licenses are intended to guarantee your freedom to share and change
  27free software--to make sure the software is free for all its users.
  28
  29  This license, the Lesser General Public License, applies to some
  30specially designated software packages--typically libraries--of the
  31Free Software Foundation and other authors who decide to use it.  You
  32can use it too, but we suggest you first think carefully about whether
  33this license or the ordinary General Public License is the better
  34strategy to use in any particular case, based on the explanations below.
  35
  36  When we speak of free software, we are referring to freedom of use,
  37not price.  Our General Public Licenses are designed to make sure that
  38you have the freedom to distribute copies of free software (and charge
  39for this service if you wish); that you receive source code or can get
  40it if you want it; that you can change the software and use pieces of
  41it in new free programs; and that you are informed that you can do
  42these things.
  43
  44  To protect your rights, we need to make restrictions that forbid
  45distributors to deny you these rights or to ask you to surrender these
  46rights.  These restrictions translate to certain responsibilities for
  47you if you distribute copies of the library or if you modify it.
  48
  49  For example, if you distribute copies of the library, whether gratis
  50or for a fee, you must give the recipients all the rights that we gave
  51you.  You must make sure that they, too, receive or can get the source
  52code.  If you link other code with the library, you must provide
  53complete object files to the recipients, so that they can relink them
  54with the library after making changes to the library and recompiling
  55it.  And you must show them these terms so they know their rights.
  56
  57  We protect your rights with a two-step method: (1) we copyright the
  58library, and (2) we offer you this license, which gives you legal
  59permission to copy, distribute and/or modify the library.
  60
  61  To protect each distributor, we want to make it very clear that
  62there is no warranty for the free library.  Also, if the library is
  63modified by someone else and passed on, the recipients should know
  64that what they have is not the original version, so that the original
  65author's reputation will not be affected by problems that might be
  66introduced by others.
  67\f
  68  Finally, software patents pose a constant threat to the existence of
  69any free program.  We wish to make sure that a company cannot
  70effectively restrict the users of a free program by obtaining a
  71restrictive license from a patent holder.  Therefore, we insist that
  72any patent license obtained for a version of the library must be
  73consistent with the full freedom of use specified in this license.
  74
  75  Most GNU software, including some libraries, is covered by the
  76ordinary GNU General Public License.  This license, the GNU Lesser
  77General Public License, applies to certain designated libraries, and
  78is quite different from the ordinary General Public License.  We use
  79this license for certain libraries in order to permit linking those
  80libraries into non-free programs.
  81
  82  When a program is linked with a library, whether statically or using
  83a shared library, the combination of the two is legally speaking a
  84combined work, a derivative of the original library.  The ordinary
  85General Public License therefore permits such linking only if the
  86entire combination fits its criteria of freedom.  The Lesser General
  87Public License permits more lax criteria for linking other code with
  88the library.
  89
  90  We call this license the "Lesser" General Public License because it
  91does Less to protect the user's freedom than the ordinary General
  92Public License.  It also provides other free software developers Less
  93of an advantage over competing non-free programs.  These disadvantages
  94are the reason we use the ordinary General Public License for many
  95libraries.  However, the Lesser license provides advantages in certain
  96special circumstances.
  97
  98  For example, on rare occasions, there may be a special need to
  99encourage the widest possible use of a certain library, so that it becomes
 100a de-facto standard.  To achieve this, non-free programs must be
 101allowed to use the library.  A more frequent case is that a free
 102library does the same job as widely used non-free libraries.  In this
 103case, there is little to gain by limiting the free library to free
 104software only, so we use the Lesser General Public License.
 105
 106  In other cases, permission to use a particular library in non-free
 107programs enables a greater number of people to use a large body of
 108free software.  For example, permission to use the GNU C Library in
 109non-free programs enables many more people to use the whole GNU
 110operating system, as well as its variant, the GNU/Linux operating
 111system.
 112
 113  Although the Lesser General Public License is Less protective of the
 114users' freedom, it does ensure that the user of a program that is
 115linked with the Library has the freedom and the wherewithal to run
 116that program using a modified version of the Library.
 117
 118  The precise terms and conditions for copying, distribution and
 119modification follow.  Pay close attention to the difference between a
 120"work based on the library" and a "work that uses the library".  The
 121former contains code derived from the library, whereas the latter must
 122be combined with the library in order to run.
 123\f
 124                  GNU LESSER GENERAL PUBLIC LICENSE
 125   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
 126
 127  0. This License Agreement applies to any software library or other
 128program which contains a notice placed by the copyright holder or
 129other authorized party saying it may be distributed under the terms of
 130this Lesser General Public License (also called "this License").
 131Each licensee is addressed as "you".
 132
 133  A "library" means a collection of software functions and/or data
 134prepared so as to be conveniently linked with application programs
 135(which use some of those functions and data) to form executables.
 136
 137  The "Library", below, refers to any such software library or work
 138which has been distributed under these terms.  A "work based on the
 139Library" means either the Library or any derivative work under
 140copyright law: that is to say, a work containing the Library or a
 141portion of it, either verbatim or with modifications and/or translated
 142straightforwardly into another language.  (Hereinafter, translation is
 143included without limitation in the term "modification".)
 144
 145  "Source code" for a work means the preferred form of the work for
 146making modifications to it.  For a library, complete source code means
 147all the source code for all modules it contains, plus any associated
 148interface definition files, plus the scripts used to control compilation
 149and installation of the library.
 150
 151  Activities other than copying, distribution and modification are not
 152covered by this License; they are outside its scope.  The act of
 153running a program using the Library is not restricted, and output from
 154such a program is covered only if its contents constitute a work based
 155on the Library (independent of the use of the Library in a tool for
 156writing it).  Whether that is true depends on what the Library does
 157and what the program that uses the Library does.
 158
 159  1. You may copy and distribute verbatim copies of the Library's
 160complete source code as you receive it, in any medium, provided that
 161you conspicuously and appropriately publish on each copy an
 162appropriate copyright notice and disclaimer of warranty; keep intact
 163all the notices that refer to this License and to the absence of any
 164warranty; and distribute a copy of this License along with the
 165Library.
 166
 167  You may charge a fee for the physical act of transferring a copy,
 168and you may at your option offer warranty protection in exchange for a
 169fee.
 170\f
 171  2. You may modify your copy or copies of the Library or any portion
 172of it, thus forming a work based on the Library, and copy and
 173distribute such modifications or work under the terms of Section 1
 174above, provided that you also meet all of these conditions:
 175
 176    a) The modified work must itself be a software library.
 177
 178    b) You must cause the files modified to carry prominent notices
 179    stating that you changed the files and the date of any change.
 180
 181    c) You must cause the whole of the work to be licensed at no
 182    charge to all third parties under the terms of this License.
 183
 184    d) If a facility in the modified Library refers to a function or a
 185    table of data to be supplied by an application program that uses
 186    the facility, other than as an argument passed when the facility
 187    is invoked, then you must make a good faith effort to ensure that,
 188    in the event an application does not supply such function or
 189    table, the facility still operates, and performs whatever part of
 190    its purpose remains meaningful.
 191
 192    (For example, a function in a library to compute square roots has
 193    a purpose that is entirely well-defined independent of the
 194    application.  Therefore, Subsection 2d requires that any
 195    application-supplied function or table used by this function must
 196    be optional: if the application does not supply it, the square
 197    root function must still compute square roots.)
 198
 199These requirements apply to the modified work as a whole.  If
 200identifiable sections of that work are not derived from the Library,
 201and can be reasonably considered independent and separate works in
 202themselves, then this License, and its terms, do not apply to those
 203sections when you distribute them as separate works.  But when you
 204distribute the same sections as part of a whole which is a work based
 205on the Library, the distribution of the whole must be on the terms of
 206this License, whose permissions for other licensees extend to the
 207entire whole, and thus to each and every part regardless of who wrote
 208it.
 209
 210Thus, it is not the intent of this section to claim rights or contest
 211your rights to work written entirely by you; rather, the intent is to
 212exercise the right to control the distribution of derivative or
 213collective works based on the Library.
 214
 215In addition, mere aggregation of another work not based on the Library
 216with the Library (or with a work based on the Library) on a volume of
 217a storage or distribution medium does not bring the other work under
 218the scope of this License.
 219
 220  3. You may opt to apply the terms of the ordinary GNU General Public
 221License instead of this License to a given copy of the Library.  To do
 222this, you must alter all the notices that refer to this License, so
 223that they refer to the ordinary GNU General Public License, version 2,
 224instead of to this License.  (If a newer version than version 2 of the
 225ordinary GNU General Public License has appeared, then you can specify
 226that version instead if you wish.)  Do not make any other change in
 227these notices.
 228\f
 229  Once this change is made in a given copy, it is irreversible for
 230that copy, so the ordinary GNU General Public License applies to all
 231subsequent copies and derivative works made from that copy.
 232
 233  This option is useful when you wish to copy part of the code of
 234the Library into a program that is not a library.
 235
 236  4. You may copy and distribute the Library (or a portion or
 237derivative of it, under Section 2) in object code or executable form
 238under the terms of Sections 1 and 2 above provided that you accompany
 239it with the complete corresponding machine-readable source code, which
 240must be distributed under the terms of Sections 1 and 2 above on a
 241medium customarily used for software interchange.
 242
 243  If distribution of object code is made by offering access to copy
 244from a designated place, then offering equivalent access to copy the
 245source code from the same place satisfies the requirement to
 246distribute the source code, even though third parties are not
 247compelled to copy the source along with the object code.
 248
 249  5. A program that contains no derivative of any portion of the
 250Library, but is designed to work with the Library by being compiled or
 251linked with it, is called a "work that uses the Library".  Such a
 252work, in isolation, is not a derivative work of the Library, and
 253therefore falls outside the scope of this License.
 254
 255  However, linking a "work that uses the Library" with the Library
 256creates an executable that is a derivative of the Library (because it
 257contains portions of the Library), rather than a "work that uses the
 258library".  The executable is therefore covered by this License.
 259Section 6 states terms for distribution of such executables.
 260
 261  When a "work that uses the Library" uses material from a header file
 262that is part of the Library, the object code for the work may be a
 263derivative work of the Library even though the source code is not.
 264Whether this is true is especially significant if the work can be
 265linked without the Library, or if the work is itself a library.  The
 266threshold for this to be true is not precisely defined by law.
 267
 268  If such an object file uses only numerical parameters, data
 269structure layouts and accessors, and small macros and small inline
 270functions (ten lines or less in length), then the use of the object
 271file is unrestricted, regardless of whether it is legally a derivative
 272work.  (Executables containing this object code plus portions of the
 273Library will still fall under Section 6.)
 274
 275  Otherwise, if the work is a derivative of the Library, you may
 276distribute the object code for the work under the terms of Section 6.
 277Any executables containing that work also fall under Section 6,
 278whether or not they are linked directly with the Library itself.
 279\f
 280  6. As an exception to the Sections above, you may also combine or
 281link a "work that uses the Library" with the Library to produce a
 282work containing portions of the Library, and distribute that work
 283under terms of your choice, provided that the terms permit
 284modification of the work for the customer's own use and reverse
 285engineering for debugging such modifications.
 286
 287  You must give prominent notice with each copy of the work that the
 288Library is used in it and that the Library and its use are covered by
 289this License.  You must supply a copy of this License.  If the work
 290during execution displays copyright notices, you must include the
 291copyright notice for the Library among them, as well as a reference
 292directing the user to the copy of this License.  Also, you must do one
 293of these things:
 294
 295    a) Accompany the work with the complete corresponding
 296    machine-readable source code for the Library including whatever
 297    changes were used in the work (which must be distributed under
 298    Sections 1 and 2 above); and, if the work is an executable linked
 299    with the Library, with the complete machine-readable "work that
 300    uses the Library", as object code and/or source code, so that the
 301    user can modify the Library and then relink to produce a modified
 302    executable containing the modified Library.  (It is understood
 303    that the user who changes the contents of definitions files in the
 304    Library will not necessarily be able to recompile the application
 305    to use the modified definitions.)
 306
 307    b) Use a suitable shared library mechanism for linking with the
 308    Library.  A suitable mechanism is one that (1) uses at run time a
 309    copy of the library already present on the user's computer system,
 310    rather than copying library functions into the executable, and (2)
 311    will operate properly with a modified version of the library, if
 312    the user installs one, as long as the modified version is
 313    interface-compatible with the version that the work was made with.
 314
 315    c) Accompany the work with a written offer, valid for at
 316    least three years, to give the same user the materials
 317    specified in Subsection 6a, above, for a charge no more
 318    than the cost of performing this distribution.
 319
 320    d) If distribution of the work is made by offering access to copy
 321    from a designated place, offer equivalent access to copy the above
 322    specified materials from the same place.
 323
 324    e) Verify that the user has already received a copy of these
 325    materials or that you have already sent this user a copy.
 326
 327  For an executable, the required form of the "work that uses the
 328Library" must include any data and utility programs needed for
 329reproducing the executable from it.  However, as a special exception,
 330the materials to be distributed need not include anything that is
 331normally distributed (in either source or binary form) with the major
 332components (compiler, kernel, and so on) of the operating system on
 333which the executable runs, unless that component itself accompanies
 334the executable.
 335
 336  It may happen that this requirement contradicts the license
 337restrictions of other proprietary libraries that do not normally
 338accompany the operating system.  Such a contradiction means you cannot
 339use both them and the Library together in an executable that you
 340distribute.
 341\f
 342  7. You may place library facilities that are a work based on the
 343Library side-by-side in a single library together with other library
 344facilities not covered by this License, and distribute such a combined
 345library, provided that the separate distribution of the work based on
 346the Library and of the other library facilities is otherwise
 347permitted, and provided that you do these two things:
 348
 349    a) Accompany the combined library with a copy of the same work
 350    based on the Library, uncombined with any other library
 351    facilities.  This must be distributed under the terms of the
 352    Sections above.
 353
 354    b) Give prominent notice with the combined library of the fact
 355    that part of it is a work based on the Library, and explaining
 356    where to find the accompanying uncombined form of the same work.
 357
 358  8. You may not copy, modify, sublicense, link with, or distribute
 359the Library except as expressly provided under this License.  Any
 360attempt otherwise to copy, modify, sublicense, link with, or
 361distribute the Library is void, and will automatically terminate your
 362rights under this License.  However, parties who have received copies,
 363or rights, from you under this License will not have their licenses
 364terminated so long as such parties remain in full compliance.
 365
 366  9. You are not required to accept this License, since you have not
 367signed it.  However, nothing else grants you permission to modify or
 368distribute the Library or its derivative works.  These actions are
 369prohibited by law if you do not accept this License.  Therefore, by
 370modifying or distributing the Library (or any work based on the
 371Library), you indicate your acceptance of this License to do so, and
 372all its terms and conditions for copying, distributing or modifying
 373the Library or works based on it.
 374
 375  10. Each time you redistribute the Library (or any work based on the
 376Library), the recipient automatically receives a license from the
 377original licensor to copy, distribute, link with or modify the Library
 378subject to these terms and conditions.  You may not impose any further
 379restrictions on the recipients' exercise of the rights granted herein.
 380You are not responsible for enforcing compliance by third parties with
 381this License.
 382\f
 383  11. If, as a consequence of a court judgment or allegation of patent
 384infringement or for any other reason (not limited to patent issues),
 385conditions are imposed on you (whether by court order, agreement or
 386otherwise) that contradict the conditions of this License, they do not
 387excuse you from the conditions of this License.  If you cannot
 388distribute so as to satisfy simultaneously your obligations under this
 389License and any other pertinent obligations, then as a consequence you
 390may not distribute the Library at all.  For example, if a patent
 391license would not permit royalty-free redistribution of the Library by
 392all those who receive copies directly or indirectly through you, then
 393the only way you could satisfy both it and this License would be to
 394refrain entirely from distribution of the Library.
 395
 396If any portion of this section is held invalid or unenforceable under any
 397particular circumstance, the balance of the section is intended to apply,
 398and the section as a whole is intended to apply in other circumstances.
 399
 400It is not the purpose of this section to induce you to infringe any
 401patents or other property right claims or to contest validity of any
 402such claims; this section has the sole purpose of protecting the
 403integrity of the free software distribution system which is
 404implemented by public license practices.  Many people have made
 405generous contributions to the wide range of software distributed
 406through that system in reliance on consistent application of that
 407system; it is up to the author/donor to decide if he or she is willing
 408to distribute software through any other system and a licensee cannot
 409impose that choice.
 410
 411This section is intended to make thoroughly clear what is believed to
 412be a consequence of the rest of this License.
 413
 414  12. If the distribution and/or use of the Library is restricted in
 415certain countries either by patents or by copyrighted interfaces, the
 416original copyright holder who places the Library under this License may add
 417an explicit geographical distribution limitation excluding those countries,
 418so that distribution is permitted only in or among countries not thus
 419excluded.  In such case, this License incorporates the limitation as if
 420written in the body of this License.
 421
 422  13. The Free Software Foundation may publish revised and/or new
 423versions of the Lesser General Public License from time to time.
 424Such new versions will be similar in spirit to the present version,
 425but may differ in detail to address new problems or concerns.
 426
 427Each version is given a distinguishing version number.  If the Library
 428specifies a version number of this License which applies to it and
 429"any later version", you have the option of following the terms and
 430conditions either of that version or of any later version published by
 431the Free Software Foundation.  If the Library does not specify a
 432license version number, you may choose any version ever published by
 433the Free Software Foundation.
 434\f
 435  14. If you wish to incorporate parts of the Library into other free
 436programs whose distribution conditions are incompatible with these,
 437write to the author to ask for permission.  For software which is
 438copyrighted by the Free Software Foundation, write to the Free
 439Software Foundation; we sometimes make exceptions for this.  Our
 440decision will be guided by the two goals of preserving the free status
 441of all derivatives of our free software and of promoting the sharing
 442and reuse of software generally.
 443
 444                            NO WARRANTY
 445
 446  15. BECAUSE THE LIBRARY IS LICENSED FREE OF CHARGE, THERE IS NO
 447WARRANTY FOR THE LIBRARY, TO THE EXTENT PERMITTED BY APPLICABLE LAW.
 448EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR
 449OTHER PARTIES PROVIDE THE LIBRARY "AS IS" WITHOUT WARRANTY OF ANY
 450KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE
 451IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 452PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE
 453LIBRARY IS WITH YOU.  SHOULD THE LIBRARY PROVE DEFECTIVE, YOU ASSUME
 454THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
 455
 456  16. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN
 457WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY
 458AND/OR REDISTRIBUTE THE LIBRARY AS PERMITTED ABOVE, BE LIABLE TO YOU
 459FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR
 460CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE
 461LIBRARY (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING
 462RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A
 463FAILURE OF THE LIBRARY TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IF
 464SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
 465DAMAGES.
 466
 467                     END OF TERMS AND CONDITIONS
 468\f
 469           How to Apply These Terms to Your New Libraries
 470
 471  If you develop a new library, and you want it to be of the greatest
 472possible use to the public, we recommend making it free software that
 473everyone can redistribute and change.  You can do so by permitting
 474redistribution under these terms (or, alternatively, under the terms of the
 475ordinary General Public License).
 476
 477  To apply these terms, attach the following notices to the library.  It is
 478safest to attach them to the start of each source file to most effectively
 479convey the exclusion of warranty; and each file should have at least the
 480"copyright" line and a pointer to where the full notice is found.
 481
 482    <one line to give the library's name and a brief idea of what it does.>
 483    Copyright (C) <year>  <name of author>
 484
 485    This library is free software; you can redistribute it and/or
 486    modify it under the terms of the GNU Lesser General Public
 487    License as published by the Free Software Foundation; either
 488    version 2.1 of the License, or (at your option) any later version.
 489
 490    This library is distributed in the hope that it will be useful,
 491    but WITHOUT ANY WARRANTY; without even the implied warranty of
 492    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 493    Lesser General Public License for more details.
 494
 495    You should have received a copy of the GNU Lesser General Public
 496    License along with this library; if not, write to the Free Software
 497    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 498
 499Also add information on how to contact you by electronic and paper mail.
 500
 501You should also get your employer (if you work as a programmer) or your
 502school, if any, to sign a "copyright disclaimer" for the library, if
 503necessary.  Here is a sample; alter the names:
 504
 505  Yoyodyne, Inc., hereby disclaims all copyright interest in the
 506  library `Frob' (a library for tweaking knobs) written by James Random Hacker.
 507
 508  <signature of Ty Coon>, 1 April 1990
 509  Ty Coon, President of Vice
 510
 511That's all there is to it!