+
+ dnl we cannot use AC_USE_SYSTEM_EXTENSIONS here, because we're way too late
+ dnl in the game, and we're currently only targeting _GNU_SOURCE for now
+ AC_MSG_CHECKING([for _GNU_SOURCE])
+ AC_EGREP_CPP([gnu_source_not_defined], [
+ #ifndef _GNU_SOURCE
+ gnu_source_not_defined
+ #endif
+ ], [
+ AC_MSG_RESULT([needs define])
+ AC_DEFINE([_GNU_SOURCE], [], [ ])
+ ], [
+ AC_MSG_RESULT([already defined])
+ ])
+