@build_afni_Xlib     - compile and install new lesstif or libXt tree
This will compile lesstif, openmotif and/or libXt, were each
of those directories should be under this 'X' directory.
    usage: @build_afni_Xlib [options] dir1 dir2 ...
There are 3 options for where the install will be:
    1. X/install          - this is the default
    2. /usr/local/afniX   - via the -afniX option
    3. X/PACKAGE/install  - via the -localinstall option
This allows for complete building of any package without
overwriting an existing one (e.g. since libXm.a is not unique).
options:
    -afniX        : install under /usr/local/afniX
                    (default is ../install)
    -g            : compile with -g to add symbols
                    (no longer the default)
    -lib32        : install libs under lib, and force 32-bit compile
                    (on Linux: add --target=i386)
    -lib64        : install libs under lib64
                    (default is lib)
    -localinstall : install under each package directory
examples:
    @build_afni_Xlib -help
    @build_afni_Xlib lesstif
    @build_afni_Xlib -afniX -lib64 openmotif libXt
    @build_afni_Xlib -lib64 -localinstall -g lesstif
note: do not install both lesstif and openmotif (of course :)
note: for compiling AFNI, set XROOT to the install dir in Makefile