* Makefile.in: eliminate the need for RUNTIME and CRT_ID.

	* Makefile.in: eliminate the need for RUNTIME and CRT_ID.
	Always build crt1.o, dllcrt1.o, crt2.o and dllcrt2.o.
	Create a libcoldname.a for the oldname library for CRTDLL.
	Restrict libmoldname.a for the oldname library for MSVCRT.
	* configure.in: eliminate setting RUNTIME and CRT_ID variables.
	Restructure the $target_os case logic.
	Always name the MinGW thread dll helper mingwm.
	Change Cygwin's HEADER_SUBDIR value from mingw32 to mingw.
	* configure: regenerate.