compilers/c_function_attributes: fix for ICC

ICC doesn't like the extra set of parens, GCC 8.2.1 and Clang 6.0.1
don't have a problem with this.

mesonbuild/compilers/c_function_attributes.py

@@ -91,10 +91,10 @@ C_FUNC_ATTRIBUTES = {
     'used':
         'int foo(void) __attribute__((used));',
     'visibility': '''
-        int foo_def(void) __attribute__((visibility(("default"))));
-        int foo_hid(void) __attribute__((visibility(("hidden"))));
-        int foo_int(void) __attribute__((visibility(("internal"))));
-        int foo_pro(void) __attribute__((visibility(("protected"))));''',
+        int foo_def(void) __attribute__((visibility("default")));
+        int foo_hid(void) __attribute__((visibility("hidden")));
+        int foo_int(void) __attribute__((visibility("internal")));
+        int foo_pro(void) __attribute__((visibility("protected")));''',
     'warning':
         'int foo(void) __attribute__((warning("")));',
     'warn_unused_result':

test cases/common/204 function attributes/meson.build

@@ -63,7 +63,7 @@ if host_machine.system() != 'darwin'
   attributes += 'visibility'
 endif
 
-if c.get_id() == 'gcc'
+if ['gcc', 'intel'].contains(c.get_id())
   # not supported by clang as of 5.0.0 (at least up to 6.0.1)
   attributes += 'artificial'
   attributes += 'error'
@@ -73,7 +73,7 @@ if c.get_id() == 'gcc'
   attributes += 'optimize'
   attributes += 'warning'
 
-  if c.version().version_compare('>= 7.0.0')
+  if c.get_id() == 'gcc' and c.version().version_compare('>= 7.0.0')
     attributes += 'fallthrough'
   endif
 endif