patch 8.2.4990: memory leak when :defcompile fails

Problem:    Memory leak when :defcompile fails.
Solution:   Free fname when returning early.

src/userfunc.c

@@ -5037,6 +5037,7 @@ find_func_by_name(char_u *name, compiletype_T *compile_type)
     }
     if (!ends_excmd2(name, arg))
     {
+	vim_free(fname);
 	emsg(ex_errmsg(e_trailing_characters_str, arg));
 	return NULL;
     }

src/version.c

@@ -746,6 +746,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4990,
 /**/
     4989,
 /**/