re PR testsuite/38526 (WARNING: Could not compile gcc.dg/compat/struct-layout-1 gener...

re PR testsuite/38526 (WARNING: Could not compile gcc.dg/compat/struct-layout-1 generator)

gcc/
	PR testsuite/38526
	* Makefile.in (site.exp): Rename TEST_GCC_EXEC_PREFIX and comment
	its use.
	(check-%): Don't set GCC_EXEC_PREFIX when invoking runtest.
	(check-parallel-%): Ditto.
	(check-consistency): Ditto.
testsuite/
	PR testsuite/38526
	* lib/target-libpath.exp (set_ld_library_path_env_vars): Save
	existing GCC_EXEC_PREFIX, set to TEST_GCC_EXEC_PREFIX if that
	is defined.
	(restore_ld_library_path_env_vars): Restore GCC_EXEC_PREFIX to
	its original value, or unset if it was not defined.
	* gcc.dg/compat/struct-layout-1.exp: Use set/restore library
	path procs around use of HOSTCC.
	* g++.dg/compat/struct-layout-1.exp: Ditto.
	* objc.dg/gnu-encoding/gnu-encoding.exp: Ditto.

From-SVN: r144908