Handle empty C comments in preprocessor

src/libclang/preprocessor.cpp

@@ -321,7 +321,10 @@ namespace
             return false;
         p.skip(2u);
 
-        if (in_main_file && starts_with(p, "*"))
+        if (starts_with(p, "*/"))
+            // empty comment
+            p.skip(2u);
+        else if (in_main_file && starts_with(p, "*"))
         {
             // doc comment
             p.skip();

test/cpp_preprocessor.cpp

@@ -182,7 +182,7 @@ using j = int;
 
 /// k
 /// k
-template <typename T>
+template <typename T/**/>
 void k();
 )";