ntpl: fix static linking by not leaking SSP_ALL_CFLAGS

ntpl: fix static linking by not leaking SSP_ALL_CFLAGS

The SSP_ALL_CFLAGS in nptl arch CFLAGS leaks out and forces things
like dl-support.c, brk.c, sbrk.c memcpy, etc to be built with
-fstack-protector-all. This is bad when linking statically since
initializing TLS will call those functions before SSP is initialized.

The libpthread itself will still be built with -fstack-protector-all
due to CFLAGS-nptl has SSP_ALL_CFLAGS in libpthread/nptl/Makefile.in

Thanks to Timo Teras for helping with this.

Signed-off-by: Natanael Copa <natanael.copa@gmail.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>