The GUI application and library share some object files but don't
enable object renaming resulting in the second compilation overwriting
the results of the first compilation. This can be fixed by setting
explicit preprocessor flags for one compilation. The actual problem,
however, is that recursive make is used in an inappropriate way; two
Makefiles shouldn't refer to the same source files. In this case,
libslvs should be under src/ and handled by the same Makefile, in
which case the issue would have been obvious when the Makefile was
written in the first place.
The libslvs library and CDemo program can now be built by Autotools. A few
code changes were needed for this: C++ comments in C code had to be
converted, constraint.cpp required some massaging, and fltkutil.cpp needed
a stub for InitHeaps().