[X86, Darwin] Backport fix for pr82920 (part 2).

[X86, Darwin] Backport fix for pr82920 (part 2).

Darwin doesn't support mx32, and some tests were
failing because it was trying to do them.  When we
disable this it turns out that quite a few tests
requiring mx32 support were not guarded.

gcc/

2019-09-28  Iain Sandoe  <iain@sandoe.co.uk>

	Backport from mainline.
	2019-05-12  Iain Sandoe  <iain@sandoe.co.uk>

	PR target/82920
	* config/i386/darwin.h (CC1_SPEC): Report -mx32 as an error for
	Darwin.

gcc/testsuite/

2019-09-28  Iain Sandoe  <iain@sandoe.co.uk>

	Backport from mainline.
	2019-05-14  Iain Sandoe  <iain@sandoe.co.uk>

	PR target/82920
	* gcc.target/i386/pr52146.c: Require effective target x32.
	* gcc.target/i386/pr52698.c: Likewise.
	* gcc.target/i386/pr52857-1.c: Likewise.
	* gcc.target/i386/pr52857-2.c: Likewise.
	* gcc.target/i386/pr52876.c: Likewise.
	* gcc.target/i386/pr53698.c: Likewise.
	* gcc.target/i386/pr54157.c: Likewise.
	* gcc.target/i386/pr55049-1.c: Likewise.
	* gcc.target/i386/pr55093.c: Likewise.
	* gcc.target/i386/pr55116-1.c: Likewise.
	* gcc.target/i386/pr55116-2.c: Likewise.
	* gcc.target/i386/pr55597.c: Likewise.
	* gcc.target/i386/pr59929.c: Likewise.
	* gcc.target/i386/pr66470.c: Likewise.

From-SVN: r276258