Properly set flag_pie and flag_pic

Properly set flag_pie and flag_pic

We can't set flag_pie to the default when flag_pic == 0, which may be
set by -fno-pic or -fno-PIC, since the default value of flag_pie is
non-zero when GCC is configured with --enable-default-pie.  We need
to initialize flag_pic to -1 so that we can tell if -fpic, -fPIC,
-fno-pic or -fno-PIC is used.

Since Darwin defaults to PIC (__PIC__ == 2) and the PIC setting can't
be changed, skip tests of default __PIC__ and __PIE__ setting for
*-*-darwin* targets.

gcc/

	PR driver/70192
	* opts.c (finish_options): Don't set flag_pie to the default if
	-fpic, -fPIC, -fno-pic or -fno-PIC is used.  Set flag_pic to 0
	if it is -1.

gcc/testsuite/

	PR driver/70192
	* gcc.dg/pic-1.c: New test.
	* gcc.dg/pic-2.c: Likewise.
	* gcc.dg/pic-3.c: Likewise.
	* gcc.dg/pic-4.c: Likewise.
	* gcc.dg/pie-1.c: Likewise.
	* gcc.dg/pie-2.c: Likewise.
	* gcc.dg/pie-3.c: Likewise.
	* gcc.dg/pie-4.c: Likewise.
	* gcc.dg/pie-5.c: Likewise.
	* gcc.dg/pie-6.c: Likewise.

From-SVN: r234295