compat: Add simplified merge sort implementation from glibc

diff --git a/configure.ac b/configure.ac
index dd4b4eb9822f131f0efc746013a803c4adba02d2..85d7ef570d390d56d3ec3ba8af406eee30d700ea 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -122,6 +122,27 @@ if test -z "$NO_TCLTK"; then
     AC_SUBST(TCLTK_PATH)
   fi
 fi
+AC_CHECK_PROGS(ASCIIDOC, [asciidoc])
+if test -n "$ASCIIDOC"; then
+       AC_MSG_CHECKING([for asciidoc version])
+       asciidoc_version=`$ASCIIDOC --version 2>&1`
+       case "${asciidoc_version}" in
+       asciidoc' '8*)
+               ASCIIDOC8=YesPlease
+               AC_MSG_RESULT([${asciidoc_version} > 7])
+               ;;
+       asciidoc' '7*)
+               ASCIIDOC8=
+               AC_MSG_RESULT([${asciidoc_version}])
+               ;;
+       *)
+               ASCIIDOC8=
+               AC_MSG_RESULT([${asciidoc_version} (unknown)])
+               ;;
+       esac
+fi
+AC_SUBST(ASCIIDOC8)
+
 
 ## Checks for libraries.
 AC_MSG_NOTICE([CHECKS for libraries])
@@ -214,6 +235,12 @@ test -n "$NEEDS_SOCKET" && LIBS="$LIBS -lsocket"
 ## Checks for header files.
 AC_MSG_NOTICE([CHECKS for header files])
 #
+# Define NO_SYS_SELECT_H if you don't have sys/select.h.
+AC_CHECK_HEADER([sys/select.h],
+[NO_SYS_SELECT_H=],
+[NO_SYS_SELECT_H=UnfortunatelyYes])
+AC_SUBST(NO_SYS_SELECT_H)
+#
 # Define OLD_ICONV if your library has an old iconv(), where the second
 # (input buffer pointer) parameter is declared with type (const char **).
 AC_DEFUN([OLDICONVTEST_SRC], [[
@@ -335,6 +362,12 @@ AC_CHECK_FUNC(setenv,
 [NO_SETENV=YesPlease])
 AC_SUBST(NO_SETENV)
 #
+# Define NO_UNSETENV if you don't have unsetenv in the C library.
+AC_CHECK_FUNC(unsetenv,
+[NO_UNSETENV=],
+[NO_UNSETENV=YesPlease])
+AC_SUBST(NO_UNSETENV)
+#
 # Define NO_MKDTEMP if you don't have mkdtemp in the C library.
 AC_CHECK_FUNC(mkdtemp,
 [NO_MKDTEMP=],