Use $(INSTALL_PROGRAM_ENV) consistently.

Use $(INSTALL_PROGRAM_ENV) consistently.

binutils/
	* Makefile.am (install-exec-local): Prefix libtool invocation with
	$(INSTALL_PROGRAM_ENV).
	* Makefile.in: Regenerate.

gas/
	* Makefile.am (install-exec-bindir): Prefix libtool invocation
	with $(INSTALL_PROGRAM_ENV).
	(install-exec-tooldir): Likewise.
	* Makefile.in: Regenerate.

gold/
	* Makefile.am (install-exec-local): Prefix $(INSTALL_PROGRAM) uses
	with $(INSTALL_PROGRAM_ENV).
	* Makefile.in: Regenerate.

ld/
	* Makefile.am (install-exec-local): Prefix libtool invocation with
	$(INSTALL_PROGRAM_ENV).
	* Makefile.in: Regenerate.