In file included from libmng.h:379,
                 from libmng_chunk_io.c:230:
libmng_types.h:192:76: error: jpeglib.h: No such file or directory
In file included from libmng.h:379,
                 from libmng_chunk_io.c:230:
libmng_types.h:364: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'mngjpeg_dctmethod'
In file included from libmng_chunk_io.c:230:
libmng.h:1083: error: expected declaration specifiers or '...' before 'mngjpeg_dctmethod'
libmng.h:1236: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'mng_get_jpeg_dctmethod'
In file included from libmng_chunk_io.c:231:
libmng_data.h:755: error: expected specifier-qualifier-list before 'mngjpeg_dctmethod'
libmng_chunk_io.c: In function 'make_crc_table':
libmng_chunk_io.c:281: error: 'mng_data' has no member named 'aCRCtable'
libmng_chunk_io.c:284: error: 'mng_data' has no member named 'bCRCcomputed'
libmng_chunk_io.c: In function 'update_crc':
libmng_chunk_io.c:304: error: 'mng_data' has no member named 'bCRCcomputed'
libmng_chunk_io.c:308: error: 'mng_data' has no member named 'aCRCtable'
make: *** [libmng_chunk_io.lo] Error 1

!!! ERROR: media-libs/libmng-1.0.9 failed.
Call stack:
  ebuild.sh, line 1546:   Called dyn_compile
  ebuild.sh, line 937:   Called src_compile
  libmng-1.0.9.ebuild, line 32:   Called die

!!! (no error message)
!!! If you need support, post the topmost build error, and the call stack if relevant.