C attributes parsing fix

regression/ansi-c/gcc_attributes10/main.c

@@ -0,0 +1,19 @@
+#define STATIC_ASSERT(condition) \
+  int array##__LINE__[(condition) ? 1 : -1]
+
+#ifdef __GNUC__
+
+int  x   __attribute__ ((__vector_size__ (12), __may_alias__));
+int  x2   __attribute__ ((__may_alias__));
+int  x3   __attribute__ ((__may_alias__, __vector_size__ (12)));
+
+STATIC_ASSERT(sizeof(x)==12);
+STATIC_ASSERT(sizeof(x2)==sizeof(int));
+STATIC_ASSERT(sizeof(x3)==12);
+
+#endif
+
+int main(int argc, char* argv[])
+{
+  return 0;
+}

regression/ansi-c/gcc_attributes10/test.desc

@@ -0,0 +1,8 @@
+CORE
+main.c
+
+^EXIT=0$
+^SIGNAL=0$
+--
+^warning: ignoring
+^CONVERSION ERROR$

regression/ansi-c/gcc_attributes5/test.desc

@@ -1,4 +1,4 @@
-KNOWNBUG
+CORE
 main.c
 
 ^EXIT=0$

src/ansi-c/parser.y

@@ -1545,7 +1545,7 @@ gcc_attribute_list:
           gcc_attribute
         | gcc_attribute_list ',' gcc_attribute
         {
-          $$=merge($1, $2);
+          $$=merge($1, $3);
         }
         ;