override default path creation when path must be from root

The default file path is always the primary mod user directory, however
some files are only ever created and read from the root user directory.
This allows for an override in such cases so that the location_flags
variable will match the intended root path.

Fixes #4384

Author: notimaginative

code/cfile/cfilesystem.cpp

@@ -1981,15 +1981,27 @@ int cf_get_file_list_preallocated(int max, char arr[][MAX_FILENAME_LEN], char**
 // Output:  path      - Fully qualified pathname.
 //Returns 0 if the result would be too long (invalid result)
 int cf_create_default_path_string(char* path, uint path_max, int pathtype, const char* filename, bool localize,
-                                  uint32_t location_flags)
+                                  uint32_t _location_flags)
 {
+	uint32_t location_flags = _location_flags;
+
 	if ( filename && strchr(filename, DIR_SEPARATOR_CHAR) ) {
 		// Already has full path
 		strncpy( path, filename, path_max );
 
 	} else {
 		cf_root* root = nullptr;
 
+		// override location flags for path types which should always come from the root (NOT mod directories)
+		// NOTE: cache directories should NOT be added here to avoid possible mod breakage
+		switch(pathtype) {
+			case CF_TYPE_PLAYERS:
+			case CF_TYPE_MULTI_PLAYERS:
+			case CF_TYPE_SINGLE_PLAYERS:
+				location_flags = CF_LOCATION_ROOT_USER | CF_LOCATION_ROOT_GAME | CF_LOCATION_TYPE_ROOT;
+				break;
+		}
+
 		for (auto i = 0; i < Num_roots; ++i) {
 			auto current_root = cf_get_root(i);