Now that we have a 2-pass build it is no longer necessary to disable
-Werror in glibc.
This partially reverts commits 6ca5f91f ("Disable -Werror for GLIBC for
all ARCH for GCC11."), 215432d3 ("config/libc: Extend glibc 2.32
workaround to include sparc") and 645ee124 ("glibc: Don't build with
-Werror for powerpc64+glibc-2.32").
Signed-off-by: Chris Packham <judge.packham@gmail.com>