-=WARNING=-  -=WARNING=-  -=WARNING=-  -=WARNING=-  -=WARNING=- 
I couldn't figure out what OS you're using, or I don't support it.
You should edit your Makefile.PL and change the include and lib paths!
Checking if your kit is complete...
Looks good
Note (probably harmless): No library found for -llibmng.lib
Writing Makefile for Graphics::MNG
cp MNG.pm blib/lib/Graphics/MNG.pm
AutoSplitting blib/lib/Graphics/MNG.pm (blib/lib/auto/Graphics/MNG)
cp lib/libmng.lib blib/lib/libmng.lib
/home/cpanrun/parisc2.0-lp64/build/5.8.2/bin/perl /home/cpanrun/parisc2.0-lp64/build/5.8.2/lib/5.8.2/ExtUtils/xsubpp  -typemap /home/cpanrun/parisc2.0-lp64/build/5.8.2/lib/5.8.2/ExtUtils/typemap -typemap typemap  MNG.xs > MNG.xsc && mv MNG.xsc MNG.c
cc -c  -I. -I../../../Gd/jpeg-6b -I../../../Gd/zlib-1.1.3 -I../../../libmng/libmng -I../../../libmng/lcms/src  -D_POSIX_C_SOURCE=199506L -D_REENTRANT -Ae -D_HPUX_SOURCE -Wl,+vnocompatwarnings +DD64 -DNO_HASH_SEED -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -fast +Onolimit +Opromote_indirect_calls   -DVERSION=\"0.04\" -DXS_VERSION=\"0.04\" +Z "-I/home/cpanrun/parisc2.0-lp64/build/5.8.2/lib/5.8.2/PA-RISC2.0-thread-multi-LP64/CORE"  -DMNG_FULL_CMS -DMNG_USE_SO -DNON_WINDOWS -DMNG_INTERNAL_MEMMNGMT -DMNG_SUPPORT_TRACE  MNG.c
cpp: "MNG.xs", line 26: error 4036: Can't open include file 'Lcms.h'.
cpp: "MNG.xs", line 27: error 4036: Can't open include file 'libmng.h'.
cpp: "MNG.xs", line 28: error 4036: Can't open include file 'libmng_types.h'.
cpp: "MNG.xs", line 29: error 4036: Can't open include file 'libmng_conf.h'.
make: *** [MNG.o] Error 1