Append to HOST_LIBGCC2_CFLAGS in libgcc

	* config.host (tmake_file): Correct comment.
	(bfin*-elf*): Remove bfin/t-elf from tmake_file, add
	t-libgcc-pic.
	(bfin*-uclinux*): Likewise.
	(bfin*-linux-uclibc*): Likewise.
	(xstormy16-*-elf): Add stormy16/t-stormy16 to tmake_file.

	* config/arm/t-elf (HOST_LIBGCC2_CFLAGS): Append instead of
	assigning.
	* config/arm/t-strongarm-elf (HOST_LIBGCC2_CFLAGS): Likewise.
	* config/avr/t-avr (HOST_LIBGCC2_CFLAGS): Likewise.
	* config/c6x/t-elf (HOST_LIBGCC2_CFLAGS): Likewise.
	* config/h8300/t-h8300 (HOST_LIBGCC2_CFLAGS): Likewise.
	* config/lm32/t-elf (HOST_LIBGCC2_CFLAGS): Likewise.
	* config/m32r/t-m32r (HOST_LIBGCC2_CFLAGS): Likewise.
	* config/mcore/t-mcore (HOST_LIBGCC2_CFLAGS): Likewise.
	* config/mips/t-elf (HOST_LIBGCC2_CFLAGS): Likewise.
	* config/mmix/t-mmix (HOST_LIBGCC2_CFLAGS): Likewise.
	* config/pdp11/t-pdp11 (HOST_LIBGCC2_CFLAGS): Likewise.
	* config/picochip/t-picochip (HOST_LIBGCC2_CFLAGS): Likewise.
	* config/stormy16/t-stormy16 (HOST_LIBGCC2_CFLAGS): Likewise.
	* config/t-openbsd-thread (HOST_LIBGCC2_CFLAGS): Likewise.

	* config/bfin/t-elf: Remove.
	* config/t-vxworks (HOST_LIBGCC2_CFLAGS): Remove.

From-SVN: r181098