[newbie] what is Xm?

[trickster]

Okay, in Mandrake 7.1, I am tying to compile a text editor, why? just
cause. ....
When I run make it keep telling me that it cannot find    "Xm.h"......in
the ~X11R6/lib dir....I have looked
elsewhere and can't fine. Does anyone know what package this belongs
to.....Thanks in advance.....Brian