more useful LINUX/UNIX defines

stepmania/configure.ac

@@ -200,17 +200,20 @@ AC_CHECK_DECL(truncf, , AC_DEFINE([NEED_TRUNCF],1,[Need truncf]), [#include <mat
 
 AC_CHECK_DECLS([SIGPWR],,,[#include <signal.h>])
 
+# Define UNIX for all Unix-like systems.  Don't define it for cross-compiling to
+# non-Unix-like systems.  (-DUNIX selects the archutils and ArchHooks to use; if
+# your platform doesn't use the Unix ones, you probably don't want to define UNIX.)
 case $host in
-	# This is just a general define for things we do in Linux that aren't
-	# yet fully generalized.  It should probably be defined in other *nixes,
-	# too.
-	*)
-		AC_DEFINE(LINUX, 1, [Linux])
-		;;
+*-linux-*)
+	AC_DEFINE(LINUX, 1, [Linux])
+	AC_DEFINE(UNIX, 1, [Unix])
+	;;
+
+*)
+	AC_DEFINE(UNIX, 1, [Unix])
+	;;
 esac
 
-# If you're using autoconf, you're in "Unix", as far as we're concerned.
-AC_DEFINE(UNIX, 1, [Unix])
 
 AC_ARG_ENABLE(tests, AC_HELP_STRING([--enable-tests], [Build test programs]), enable_tests=$enableval, enable_tests=no)
 AM_CONDITIONAL(BUILD_TESTS, test "$enable_tests" = "yes" )