git head wont build for non-NPTL config.

[Tony Wu]

commit 18e7136e79a89ba5e978f0dc445a8fcf8d619a40 broke build for
non-NPT config. The new logic is the reverse of the old one.

+CSRC-$(UCLIBC_HAS_THREADS_NATIVE) += fork.c getpid.c raise.c open.c close.c \
+	read.c write.c
-ifeq ($(UCLIBC_HAS_THREADS_NATIVE),y)
-CSRC := $(filter-out fork.c getpid.c raise.c open.c close.c read.c
write.c, $(CSRC))

Tony