xlibs-dev not found on s390 during configure

[Chris Cheney <ccheney@cheney.cx>]

Does anyone know why this would fail on s390 buildd? It works on the
other buildds fine.

Please cc: me on replies.

Thanks,

Chris

configure:23025: checking for X
configure:23071: gcc -E  conftest.c
configure:23077: $? = 0
configure:23168: gcc -o conftest -ansi -W -Wall -pedantic -Wshadow
+-Wpointer-arith -Wmissing-prototypes -Wwrite-strings -D_XOPEN_SOURCE=500
+-D_BSD_SOURCE -DNDEBUG -O2     conftest.c -lXt  >&5
configure: In function `main':
configure:23232: warning: implicit declaration of function `XtMalloc'
/usr/bin/ld: cannot find -lXt
collect2: ld returned 1 exit status
configure:23171: $? = 1