configure.ac: Check for sys/ipc.h and sys/sem.h.

	* configure.ac: Check for sys/ipc.h and sys/sem.h.
	* config.h.in: Regenerated.
	* configure: Likewise.
	* testsuite/testsuite_hooks.cc (_GLIBCXX_SYSV_SEM): Conditionally
	define.
	(sys/types.h): Include.
	(sys/ipc.h): Likewise.
	(sys/sem.h): Likewise.
	(__gnu_test::semun): New type.
	(__gnu_test::semaphore::sempaphore): New function.
	(__gnu_test::semaphore::~semaphore): Likewise.
	(__gnu_test::semaphore::wait): Likewise.
	(__gnu_test::semaphore::signal): Likewise.
	* testsuite/testsuite_hooks.h (__gnu_test::semaphore): New class.
	* testsuite/27_io/basic_filebuf/close/char/4789.cc: Use
	semaphores, not sleep.
	* testsuite/27_io/basic_filebuf/close/char/9964.cc: Likewise.
	* testsuite/27_io/basic_filebuf/imbue/char/13171-2.cc: Likewise.
	* testsuite/27_io/basic_filebuf/imbue/char/13582-2.cc: Likewise.
	* testsuite/27_io/basic_filebuf/imbue/wchar_t/14975-2.cc:
	Likewise.
	* testsuite/27_io/basic_filebuf/open/char/9507.cc: Likewise.
	* testsuite/27_io/basic_filebuf/underflow/char/10097.cc: Likewise.
	* testsuite/27_io/objects/char/7.cc: Likewise.
	* testsuite/27_io/objects/char/9661-1.cc: Likewise.
	* testsuite/27_io/objects/wchar_t/7.cc: Likewise.
	* testsuite/27_io/objects/wchar_t/9961-1.cc: Likewise.

From-SVN: r92865