Added NXT_HAVE_C11_GENERIC.

Test if _Generic(3) is available.  Although we require GNU C11, some
old compilers, like the one in CentOS 7 still don't have full support
for C11, and _Generic(3) is not available there.

Cc: Andrew Clayton <a.clayton@nginx.com>
Signed-off-by: Alejandro Colomar <alx@kernel.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/auto/clang b/auto/clang
index 975a6468..f7f0dd64 100644
--- a/auto/clang
+++ b/auto/clang
@@ -6,6 +6,17 @@
 # C language features.
 
 
+nxt_feature="C11 _Generic()"
+nxt_feature_name=NXT_HAVE_C11_GENERIC
+nxt_feature_run=no
+nxt_feature_incs=
+nxt_feature_libs=
+nxt_feature_test="int main(void) {
+                      return _Generic(1, int: 0);
+                  }"
+. auto/feature
+
+
 nxt_feature="C99 variadic macro"
 nxt_feature_name=NXT_HAVE_C99_VARIADIC_MACRO
 nxt_feature_run=yes