scm_dynwind_block_asyncs() and scm_dynwind_unblock_asyncs() won't link

[Chris Vine <chris@cvine.freeserve.co.uk>]

Hi,

I am having a linking problem with scm_dynwind_block_asyncs() and
scm_dynwind_unblock_asyncs() with guile-2.0.11, but only with those
two functions. This can be reduced to the following test case:

  #include <libguile.h>

  int main(void)
  {
    scm_dynwind_block_asyncs();
    scm_dynwind_unblock_asyncs();
    return 0;
  }

when compiled with:

  gcc -o guile-test `pkg-config guile-2.0 --cflags --libs` guile-test.c

they fail to link for me, emitting:

  /tmp/cc3wakQm.o: In function `main':
  guile-test.c:(.text+0x12): undefined reference to `scm_dynwind_block_asyncs'
  guile-test.c:(.text+0x17): undefined reference to `scm_dynwind_unblock_asyncs'
  collect2: error: ld returned 1 exit status

However, all other guile functions appear to link correctly, and

  nm -Ca /usr/lib/libguile-2.0.so | grep scm_dynwind.*asyncs

shows the two functions are in the shared library file.  I am at a
complete loss.  Can someone test their own installations of guile-2.0.11
and/or tell me what I might be doing wrong?

Chris