Support inline/__inline

src/parser/parser.l

@@ -99,6 +99,7 @@ extern              return EXTERN;
 auto                return AUTO;
 register            return REGISTER;
 inline              return INLINE;
+__inline            return INLINE;
 
 struct              return STRUCT;
 union               return UNION;

src/parser/parser.yc

@@ -340,6 +340,7 @@ init_declarator
 storage_class_specifier
     : TYPEDEF
     | EXTERN
+    | INLINE
     | STATIC
     | AUTO
     | REGISTER