the ghostscript-gpl configure script has big-endian/little-endian options, and a AC_RUN_IFELSE function for detecting it. all of this should be deleted and replaced with AC_C_BIGENDIAN. autoconf handles native & cross builds fine.
you can look at the ac_cv_c_bigendian env var for the result of the test if you want to keep things like $BIGENDIAN. but it also sets up the WORDS_BIGENDIAN define for code to use.
The reason for the explicit tests is because the AC_C_BIGENDIAN test in autoconf 2.62 (which was in fairly wide spread use when I added that stuff) was known to be buggy and had a number of problems - especially on PowerPC hardware and Apple systems.
It does look like problems have been addressed in that area, so I can probably do it by updating the required version.