* langhooks.c: Don't include gt-langhooks.h.
(var_labelno): Delete.
(lhd_set_decl_assembler_name): Do not append a distinguishing
number to file-scope internal-linkage declarations for the first
input file, even if they have DECL_CONTEXT set. Use DECL_UID of
the declaration itself (if at block scope), or its containing
TRANSLATION_UNIT_DECL (if at file scope) for the distinguishing
number.
* opts.c (cur_in_fname): New global.
* opts.h: Declare it.
* tree.c: Include opts.h.
(make_node_stat): If creating a TRANSLATION_UNIT_DECL, give it
DECL_UID equal to cur_in_fname.
(copy_node_stat): Do not change DECL_UID when copying a
TRANSLATION_UNIT_DECL.
(build_common_tree_nodes): Adjust next_decl_uid to reserve the
range 0 .. num_in_fnames-1 for TRANSLATION_UNIT_DECLs.