
They aren't functions, they are character arrays. The standard strings
are either defined as string constants or character pointers into
XtShellStrings and XtStrings determined by XTSTRINGDEFINES. Your
libraries were compiled with this defined and your application with it
undefined so simply recompile one or the other. It is probably worth
adding -DXTSTRINGDEFINES to your CFLAGS.

-- 

Michael Salmon

#include	<standard.disclaimer>
#include	<witty.saying>
#include	<fancy.pseudo.graphics>