x11-toolkits/open-motif*: fix build with clang 16
Clang 16 has a new error about incompatible function types, which shows
up when building x11-toolkits/open-motif:
WmError.c:134:24: error: incompatible function pointer types passing 'void (char *)' to parameter of type 'void (*)(String) __attribute__((noreturn))' (aka 'void (*)(char *) __attribute__((noreturn))') [-Wincompatible-function-pointer-types]
XtSetErrorHandler (WmXtErrorHandler);
^~~~~~~~~~~~~~~~
/usr/local/include/X11/Intrinsic.h:1776:1: note: passing argument to parameter here
);
^In this case the declaration of the callback function for
XtSetErrorHandler() shoud have a noreturn attribute, specifically using
the _X_NORETURN macro.
PR: 271425