
From the FAQ:

Subject:  96)! What is this link problem with libXmu on SunOS 4.1.[23]?

        In SunOS 4.1.2 Sun fixed a shared-library bug in ld which conflicts
with the way X builds the shared Xmu library, causing these symbols, notably,
to be undefined when building some X11 clients:
        _get_wmShellWidgetClass
        _get_applicationShellWidgetClass
Compiling "-Bstatic -lXmu -Bdynamic" appears to work.

To solve the problem if you are using OpenWindows 3.0 (X11R4-based Xt), please
contact your local Sun office and request the following patches:

Patch i.d.      Description
100512-02       4.1.x OpenWindows 3.0 libXt Jumbo patch
100573-03       4.1.x OpenWindows 3.0 undefined symbols when using
                        shared libXmu

[Greg Earle, earle@Sun.COM; 7/92]

A source patch for use with the MIT X11R4 libraries was developed by Conrad
Kimball (cek@sdc.boeing.com); it retrofits into R4 some fixes made in R5 to
get around this problem. The patch is on export in [1/93]
        contrib/X11R4_sunos4.1.2_patch_version3.Z
