atoms: add format attribute to makenames() function

Quiets clang warning:
atoms.c:53:22: warning: format string is not a string literal [-Wformat-nonliteral]
        n = vasprintf(&ret, fmt, ap);
                            ^~~

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/src/atoms.c b/src/atoms.c
index e5c33e5..559579f 100644
--- a/src/atoms.c
+++ b/src/atoms.c
@@ -13,6 +13,14 @@
 #include <stdarg.h>
 #include "xcb_atom.h"
 
+#ifndef __has_attribute
+# define __has_attribute(x) 0  /* Compatibility with older compilers. */
+#endif
+
+#if __has_attribute(__format__)                                         \
+    || defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 203)
+__attribute__((__format__(__printf__,1,2)))
+#endif
 static char *makename(const char *fmt, ...)
 {
 	char *ret;