[PATCH] fix wrong -Wno-missing-field-initializers detection

[Frediano Ziglio]

The small code in m4/manywarnings.m4 wrongly detects if
-Wno-missing-field-initializers is needed. This happens if
-Wunused-variable is set. In this case the code fails to compile
due to -Werror even if -Wno-missing-field-initializers would be
perfectly fine.
---
 m4/manywarnings.m4 | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/m4/manywarnings.m4 b/m4/manywarnings.m4
index 89fd0ae..4f701f4 100644
--- a/m4/manywarnings.m4
+++ b/m4/manywarnings.m4
@@ -62,10 +62,11 @@ AC_DEFUN([gl_MANYWARN_ALL_GCC],
         CFLAGS="$CFLAGS -W -Werror"
         AC_COMPILE_IFELSE(
           [AC_LANG_PROGRAM(
-             [[void f (void)
+             [[int f (void)
                {
                  typedef struct { int a; int b; } s_t;
                  s_t s1 = { 0, };
+                 return s1.b;
                }
              ]],
              [[]])],
-- 
2.7.4