re PR sanitizer/81066 (sanitizer_stoptheworld_linux_libcdep.cc:276:22: error: aggregate ‘sigaltstack handler_stack’ has incomplete type and cannot be defined)

	PR sanitizer/81066
	* sanitizer_common/sanitizer_linux.h: Cherry-pick upstream r307969.
	* sanitizer_common/sanitizer_linux.cc: Likewise.
	* sanitizer_common/sanitizer_stoptheworld_linux_libcdep.cc: Likewise.
	* tsan/tsan_platform_linux.cc: Likewise.

From-SVN: r250200