Dynamic libs in the Cygwin port of GAWK - possible config bug.

[Kenny McCormack]

Disclaimer: I don't have the time or inclination to test this further.

That said:
        1) The configure script for GAWK decides whether or not to compile
in the extension() function by compiling a trivial C program with -ldl.
        2) Cygwin does seem to support dynamic libs - dlfcn.h is present
and (AFAICT) declares the needed things; however, there is no -ldl in
Cygwin-land.  Thus, the test alluded to above fails (*).

Thus, it seems that if the configure were changed, extension() could be
enabled in the Cygwin version.  However, it is unclear whether/which
Windows DLLs could/would, in fact, work with such a version.  Maybe this is
why it was left un-enabled.

(*) Note that this is not uncommon in Cygwin - namely, that some
functionality that requires an explicit -l<something> under Unix "comes for
free" (that is, is in the basic libc) in Cygwin.  I've hit this at least
once in the past when porting Unix stuff to Cygwin.