Fix s390 linknamespace fallout of bug 22702 patch.

My fix for bug 22702 introduced linknamespace test failures on
s390x-linux-gnu and s390-linux-gnu because it made remainder call
__feholdexcept, and the s390 __feholdexcept calls fegetenv, and
remainder is in Unix98 and XPG4.2 but fegetenv isn't.  This patch
makes __feholdexcept call __fegetenv instead to avoid that namespace
issue.

Tested (compilation) with build-many-glibcs.py for s390x-linux-gnu,
where it resolves the test failures.

	* sysdeps/s390/fpu/feholdexcpt.c (__feholdexcept): Call __fegetenv
	instead of fegetenv.