* gcc-interface/Makefile.in (NO_SIBLING_ADAFLAGS): Always define.
(NO_REORDER_ADAFLAGS): New variable.
(EXTRA_GNATTOOLS): Always define.
(../stamp-gnatlib1-$(RTSDIR): Copy tsystem.h.
Clean up and adjust list of files compiled with special options.
* gcc-interface/Make-lang.in: Likewise.
(ada/decl.o): Cosmetical change.
(ada/misc.o): Remove dependency on $(PLUGIN_H).