json-c uses the attribute 'cold' in one place for optimization.

ports-gcc doesn't know it so warns. So we need to disable using
-Werror in order to fix the build on sparc64

ok jca@

devel/json-c/Makefile

@@ -14,4 +14,6 @@ MASTER_SITES =		https://s3.amazonaws.com/json-c_releases/releases/
 
 MODULES=		devel/cmake
 
+CONFIGURE_ARGS=		-DDISABLE_WERROR=ON
+
 .include <bsd.port.mk>

devel/json-c/patches/patch-json_object_c

@@ -0,0 +1,17 @@
+This optimization breaks for ports-gcc. Patch it out.
+
+Index: json_object.c
+--- json_object.c.orig
++++ json_object.c
+@@ -145,10 +145,7 @@ static json_object_to_json_string_fn _json_object_user
+ #elif defined(__OS400__)
+ #define JSON_NORETURN
+ #else
+-/* 'cold' attribute is for optimization, telling the computer this code
+- * path is unlikely.
+- */
+-#define JSON_NORETURN __attribute__((noreturn, cold))
++#define JSON_NORETURN __attribute__((noreturn))
+ #endif
+ #endif
+ /**