dot-separated segment and the section name is everything before the last
dot. The variable names are case-insensitive, allow only alphanumeric
characters and `-`, and must start with an alphabetic character. Some
-variables may appear multiple times.
+variables may appear multiple times; we say then that the variable is
+multivalued.
Syntax
~~~~~~
'name = value'. If there is no equal sign on the line, the entire line
is taken as 'name' and the variable is recognized as boolean "true".
The variable names are case-insensitive, allow only alphanumeric characters
-and `-`, and must start with an alphabetic character. There can be more
-than one value for a given variable; we say then that the variable is
-multivalued.
+and `-`, and must start with an alphabetic character.
Leading and trailing whitespace in a variable value is discarded.
Internal whitespace within a variable value is retained verbatim.