MSP430: Add -fno-exceptions multilib

ChangeLog:

2019-12-11  Jozef Lawrynowicz  <jozef.l@mittosystems.com>

	* config-ml.in (msp430-*-*): Support --disable-no-exceptions configure
	flag.

gcc/ChangeLog:

2019-12-11  Jozef Lawrynowicz  <jozef.l@mittosystems.com>

	* config/msp430/msp430.h (STARTFILE_SPEC) [!fexceptions]: Use
	crtbegin_no_eh.o if building for the C language.
	[fno-exceptions]: Use crtbegin_no_eh.o if building for any language
	except C.
	(ENDFILE_SPEC) [!fexceptions]: Use crtend_no_eh.o if building for 
	the C language.
	[fno-exceptions]: Use crtend_no_eh.o if building for any language
	except C.
	* config/msp430/t-msp430: Add -fno-exceptions multilib.
	* doc/install.texi: Document --disable-no-exceptions multilib configure
	option.
	* doc/sourcebuild.texi: Document exceptions_enabled effective target.

gcc/testsuite/ChangeLog:

2019-12-11  Jozef Lawrynowicz  <jozef.l@mittosystems.com>

	* lib/gcc-dg.exp: Add dg-prune messages for when exception handling is
	disabled.
	* lib/target-supports.exp (check_effective_target_exceptions_enabled):
	New.

libgcc/ChangeLog:

2019-12-11  Jozef Lawrynowicz  <jozef.l@mittosystems.com>

	* config.host: Add crt{begin,end}_no_eh.o to "extra_parts".
	* config.host (msp430*-*-elf): Add crt{begin,end}_no_eh.o to
	"extra_parts".

From-SVN: r279246