libstdc++, libgfortran gthr workaround for musl

libstdc++, libgfortran gthr workaround for musl

On behalf of szabolcs.nagy@arm.com

[libstdc++-v3/]
2015-04-22  Szabolcs Nagy  <szabolcs.nagy@arm.com>

	* config/os/generic/os_defines.h (_GLIBCXX_GTHREAD_USE_WEAK): Define.
	* configure.host (os_include_dir): Set to "os/generic" for linux-musl*.

[libgfortran/]
2015-04-22  Szabolcs Nagy  <szabolcs.nagy@arm.com>

	* acinclude.m4 (GTHREAD_USE_WEAK): Define as 0 for *-*-musl*.
	* configure: Regenerate.

From-SVN: r222329