[PATCH 1/2] tools/nolibc: avoid -Wundef warning for __STDC_VERSION__

[Thomas Weißschuh]

With -std=c89 the macro __STDC_VERSION__ is not defined.
While undefined identifiers in '#if' directives are assumed to be '0',
with -Wundef a warning is emitted.

Avoid the warning by explicitly falling back to '0' if __STDC_VERSION__
is not provided by the preprocessor.

Fixes: 37219aa5b123 ("tools/nolibc: add __nolibc_static_assert()")
Signed-off-by: Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
---
 tools/include/nolibc/compiler.h | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/tools/include/nolibc/compiler.h b/tools/include/nolibc/compiler.h
index f03f84cfadce..dac09badff0a 100644
--- a/tools/include/nolibc/compiler.h
+++ b/tools/include/nolibc/compiler.h
@@ -47,6 +47,12 @@
 #  define __nolibc_fallthrough do { } while (0)
 #endif /* __nolibc_has_attribute(fallthrough) */
 
+#ifdef __STDC_VERSION__
+#  define __nolibc_stdc_version __STDC_VERSION__
+#else
+#  define __nolibc_stdc_version 0
+#endif
+
 #define __nolibc_version(_major, _minor, _patch) ((_major) * 10000 + (_minor) * 100 + (_patch))
 
 #ifdef __GNUC__
@@ -63,7 +69,7 @@
 #  define __nolibc_clang_version 0
 #endif /* __clang__ */
 
-#if __STDC_VERSION__ >= 201112L || \
+#if __nolibc_stdc_version >= 201112L || \
 	__nolibc_gnuc_version >= __nolibc_version(4, 6, 0) || \
 	__nolibc_clang_version >= __nolibc_version(3, 0, 0)
 #  define __nolibc_static_assert(_t) _Static_assert(_t, "")

-- 
2.53.0