Fix 695207: printf format bug in mutool info.
Fix 695105: openjpeg configuration for big-endian.

Stupid unportable code needs stupid unportable preprocessor macros.

This only works with GCC, but should be good enough since I expect
anyone using a big-endian machine to also use a GCC compatible compiler.
Fix 695098: don't use atoi() on non-zero-terminated buffer.