gdb/

* dwarf2read.c (dw2_expand_symtabs_matching): Add basenames parameter
	to the file_matcher parameter.  Pass 0 to it.
	(dwarf2_create_include_psymtab): Copy also DIRNAME.
	* psymtab.c (partial_map_symtabs_matching_filename): Drop handling of
	NULL psymtab_to_fullname result.
	(psymtab_to_fullname): Remove variable r.  Never return NULL, assemble
	an expected filename instead.
	(expand_symtabs_matching_via_partial): Add basenames parameter to the
	file_matcher parameter.  Call also psymtab_to_fullname, after newly
	considering BASENAMES_MAY_DIFFER.
	* source.c (rewrite_source_path): Remove static.
	* source.h (rewrite_source_path): New declaration.
	* symfile.h (struct quick_symbol_functions): Add basenames parameter to
	the expand_symtabs_matching field.  Comment it.
	* symtab.c (file_matches): New function comment.  Add parameter
	basenames, implement it.
	(search_symbols_file_matches): Add basenames parameter.  Update the
	file_matches caller.
	(search_symbols): Match FILES also against symtab_to_fullname.
	Optimize it for BASENAMES_MAY_DIFFER.

gdb/testsuite/
	* gdb.base/fullpath-expand-func.c: New file.
	* gdb.base/fullpath-expand.c: New file.
	* gdb.base/fullpath-expand.exp: New file.
	* gdb.base/realname-expand-real.c: New file.
	* gdb.base/realname-expand.c: New file.
	* gdb.base/realname-expand.exp: New file.

gdb/source.c

@@ -954,7 +954,7 @@ get_substitute_path_rule (const char *path)
    Return NULL if no substitution rule was specified by the user,
    or if no rule applied to the given PATH.  */
    
-static char *
+char *
 rewrite_source_path (const char *path)
 {
   const struct substitute_path_rule *rule = get_substitute_path_rule (path);