Adaptation from gentoo patch for libmng 2.0.3
See https://bugs.gentoo.org/show_bug.cgi?id=520906

Signed-off-by: Gustavo Zacarias <gustavo.zacarias@free-electrons.com>

diff -Nura libmng-2.0.3.orig/libmng_types.h libmng-2.0.3/libmng_types.h
--- libmng-2.0.3.orig/libmng_types.h	2015-09-24 10:32:05.500984924 -0300
+++ libmng-2.0.3/libmng_types.h	2015-09-24 10:33:11.145254771 -0300
@@ -200,13 +200,6 @@
 #undef FAR                             /* possibly defined by zlib or lcms */
 #endif
 #define JPEG_INTERNAL_OPTIONS          /* for RGB_PIXELSIZE */
-/* There has been a change in jpeg-9 : */
-#if !defined(HAVE_BOOLEAN) && !defined(_WIN32)
-#define HAVE_BOOLEAN
-#endif
-#ifndef _WIN32
-typedef int boolean;
-#endif
 /* For jpegsrc.v09a: */
 #include <stdio.h>
 #include <jpeglib.h>