Makefile.in (CRTSTUFF_CFLAGS): Add -fno-zero-initialized-in-bss.

	* Makefile.in (CRTSTUFF_CFLAGS): Add -fno-zero-initialized-in-bss.
	* doc/invoke.texi (-fno-zero-initialized-in-bss): Document.
	* flags.h (flag_zero_initialized_in_bss): Declare.
	* toplev.c (flag_zero_initialized_in_bss): New flag.
	(lang_independent_options): Add flag_zero_initialized_in_bss.
	* tree.c (initializer_zerop): New function.
	* tree.h (initializer_zerop): Declare.
	* varasm.c (assemble_variable): If we can emit bss, put zero
	initializers in the bss section.

From-SVN: r50218