bug#40075: guile-3.0.1: --without-threads build failure on NetBSD

Hi!

guile-2.2.7 builds fine, but when I try to build guile 3.0.1
--without-threads on NetBSD-9.99.49/amd64, I see:

  CCLD     libguile-3.0.la
ld: .libs/libguile_3.0_la-posix.o: in function `scm_tmpnam':
/scratch/wip/guile30/work/guile-3.0.1/libguile/posix.c:1605: warning: warning: tmpnam() possibly used unsafely, use mkstemp() or mkdtemp()
  CCLD     guile
ld: ./.libs/libguile-3.0.so: warning: warning: tmpnam() possibly used unsafely, use mkstemp() or mkdtemp()
ld: ./.libs/libguile-3.0.so: undefined reference to `scm_i_pthread_key_create'

Any ideas how to solve this?

Thanks,
 Thomas