+ enable => Enable specific configuration features.
+ This MUST be an array of words.
+ disable => Disable specific configuration features.
+ This MUST be an array of words.
+ Note: if the same feature is both enabled
+ and disabled, disable wins.
+
+ as => The assembler command. This is not always
+ used (for example on Unix, where the C
+ compiler is used instead).
+ asflags => Default assembler command flags [4].
+ cpp => The C preprocessor command, normally not
+ given, as the build file defaults are
+ usually good enough.
+ cppflags => Default C preprocessor flags [4].
+ defines => As an alternative, macro definitions may be
+ given here instead of in `cppflags' [4].
+ If given here, they MUST be as an array of
+ the string such as "MACRO=value", or just
+ "MACRO" for definitions without value.
+ includes => As an alternative, inclusion directories
+ may be given here instead of in `cppflags'
+ [4]. If given here, the MUST be an array
+ of strings, one directory specification
+ each.
+ cc => The C compiler command, usually one of "cc",