MSP430: Add new msp430-elfbare target

contrib/ChangeLog:

2019-12-16  Jozef Lawrynowicz  <jozef.l@mittosystems.com>

	* config-list.mk: Add msp430-elfbare.

gcc/ChangeLog:

2019-12-16  Jozef Lawrynowicz  <jozef.l@mittosystems.com>

	* config.gcc: s/msp430*-*-*/msp430-*-*.
	Handle msp430-*-elfbare.
	* config/msp430/msp430-devices.c (TARGET_SUBDIR): Define.
	(_MSPMKSTR): Define.
	(__MSPMKSTR): Define.
	(rest_of_devices_path): Use TARGET_SUBDIR value in string.
	* config/msp430/msp430.c (msp430_option_override): Error if
	-fuse-cxa-atexit is used when it has been disabled at configure time.
	* config/msp430/t-msp430: Define TARGET_SUBDIR when building
	msp430-devices.o.
	* doc/install.texi: Document msp430-*-elf and msp430-*-elfbare.
	* doc/invoke.texi: Update documentation about which path devices.csv is
	searched for.

gcc/testsuite/ChangeLog:

2019-12-16  Jozef Lawrynowicz  <jozef.l@mittosystems.com>

	* g++.dg/init/dso_handle1.C: Require cxa_atexit support.
	* g++.dg/init/dso_handle2.C: Likewise.
	* g++.dg/other/cxa-atexit1.C: Likewise.
	* gcc.target/msp430/msp430.exp: Update csv-using-installed.c test to
	handle msp430-elfbare configuration.

libgcc/ChangeLog:

2019-12-16  Jozef Lawrynowicz  <jozef.l@mittosystems.com>

	* config.host: s/msp430*-*-elf/msp430-*-elf*.
	Override default "extra_parts" variable.
	* configure: Regenerate.
	* configure.ac: Disable TM clone registry by default for
	msp430-elfbare.

From-SVN: r279442