generate #if lines for headers

1 files changed, 23 insertions, 0 deletions

diff --git a/ftm.m4 b/ftm.m4
new file mode 100644
index 00000000..5a6736da
--- /dev/null
+++ b/ftm.m4
@@ -0,0 +1,23 @@
+
+define(`STDC',
+	`ifelse($#, 2,
+		`ifelse($1, 1, `!defined __STDC_VERSION__ || __STDC_VERSION__ <= $2', `defined __STDC_VERSION__ && $1 <= __STDC_VERSION__ && __STDC_VERSION__ <= $2')',
+		`ifelse($1, 1, `', `defined __STDC_VERSION__ && $1 <= __STDC_VERSION__')')
+	')
+
+define(`POSIX',
+	`ifelse($#, 2,
+		`ifelse($1, 1, `defined _POSIX_SOURCE && (!defined _POSIX_C_SOURCE || _POSIX_C_SOURCE <= $2)', `defined _POSIX_C_SOURCE && $1 <= _POSIX_C_SOURCE && _POSIX_C_SOURCE <= $2')',
+		`ifelse($1, 1, `defined _POSIX_SOURCE', `defined _POSIX_C_SOURCE && $1 <= _POSIX_C_SOURCE')')
+	')
+
+define(`XEXT', `defined _XOPEN_SOURCE && ((defined _XOPEN_SOURCE_EXTENDED && _XOPEN_SOURCE_EXTENDED == 1) || 500 <= _XOPEN_SOURCE)')
+define(`XOPEN',
+	`ifelse($#, 2,
+		`ifelse($1, 4, `defined _XOPEN_SOURCE && _XOPEN_SOURCE <= $2',
+			`ifelse($1, 400, `XEXT() && _XOPEN_SOURCE <= $2',
+				`defined _XOPEN_SOURCE && $1 <= _XOPEN_SOURCE && _XOPEN_SOURCE <= $2')')',
+		`ifelse($1, 4, `defined _XOPEN_SOURCE',
+			`ifelse($1, 400, `XEXT())',
+				`defined _XOPEN_SOURCE && $1 <= _XOPEN_SOURCE')')')
+	')