Fortran 77 support in libtool

[Erik Lindahl]

Hi,

I originally wrote the Fortran 77 patch last summer and discussed it
with Robert Boehne.
The copyright assignment took forever, of course, so here it is again
for your comments and
hopefully eventual inclusion. The actual patch is in the next
(separate) message.

I've added Fortran 77 support by more or less duplicating the CXX parts
in libtool.m4, and
tweaking a couple of routines (like the check for -c -o, and separating
-fpic from -DPIC) where
the Fortran case has to get special treatment. The new tag is called
"F77".

There is also an extremely small demo and a test suite that does linking
with mixed fortran/C
libraries.

Cheers,

Erik Lindahl