[PATCH] Make extended allocation work without threads

[SL Baur]

This patch fixes the Alpha crash in `make check' I reported last week,
thanks.

Make check still fails:

make[2]: Entering directory `/home/work/turbo/BUILD/libc/localedata'
make[2]: *** No rule to make target `/home/work/turbo/BUILD/libc/build-alpha-linux/localedata/tst_iswalnum.o', needed by `/home/work/turbo/BUILD/libc/build-alpha-linux/localedata/tst_iswalnum'.  Stop.