Pass -no-pie to GCC only if GCC defaults to PIE [BZ #22614]

After --enable-static-pie is added to configure, libc_cv_pie_default is
set to yes when either --enable-static-pie is used to configure glibc
or GCC defaults to PIE.  We should set no-pie-ldflag to -no-pie, which
is supported on GCC 6 and later, only if GCC defaults to PIE, not when
--enable-static-pie is used to configure glibc.

Tested on x32 with --enable-static-pie using GCC 5 and without
--enable-static-pie using GCC 7.

	[BZ #22614]
	* Makeconfig (no-pie-ldflag): Set to -no-pie only if
	$(cc-pie-default) == yes.
	* config.make.in (cc-pie-default): New.
	* configure.ac (libc_cv_pie_default): Renamed to ...
	(libc_cv_cc_pie_default): This.
	(libc_cv_pie_default): Set to $libc_cv_cc_pie_default.
	* configure: Regenerated.