[XForms] missing X11 library?

[Peter Rowat]

I have what must be a trivial problem compiling a simple program:

I’ve written and compiled a few XForms programs successfully, and now I’m using some X library calls as used, e.g., in the triangle routine in “freedraw.c” demo. 

However it seems I’m missing a library since I get the following errors:

This command compiles my programs without the X library calls:

gcc -g  -I/opt/X11/include -o trime -I/Users/prowat/XFormsCode/xforms-1.2.4/lib -L/opt/X11/lib -L/usr/local/lib -lforms trime.c

Undefined symbols for architecture x86_64:

  "_XDrawLines", referenced from:

      _draw_triangle in trime-f577d6.o

  "_XFillPolygon", referenced from:

      _draw_triangle in trime-f577d6.o

  "_XSetForeground", referenced from:

      _draw_triangle in trime-f577d6.o

Thanks for any help. I’m on OS X 10.11

Peter R