collectd.h: guard define of __attribute__

It might have already been defined to a no-op in <sys/cdefs.h>

diff --git a/src/daemon/collectd.h b/src/daemon/collectd.h
index 2bfc3a2..3cb0c1b 100644 (file)
--- a/src/daemon/collectd.h
+++ b/src/daemon/collectd.h
@@ -276,7 +276,9 @@ typedef int _Bool;
 
 /* Only enable __attribute__() for compilers known to support it. */
 #if !defined(__clang__) && !defined(__GNUC__)
-# define __attribute__(x) /**/
+# if !defined(__attribute__)
+#  define __attribute__(x) /**/
+# endif
 #endif
 
 #if defined(COLLECT_DEBUG) && COLLECT_DEBUG && defined(__GNUC__) && __GNUC__