Improved pngnq源存档没有makefile（解压时要小心，没有顶级目录）。
如何在openSUSE 11.4上编译它？安装了libpng / zlib头文件和通常的C工具链。
pngnq$ gcc *.c
pngcomp.c: In function ‘main’:
pngcomp.c:111:37: error: ‘VERSION’ undeclared (first use in this function)
pngcomp.c:111:37: note: each undeclared identifier is reported only once for each function it appears in
rwpng.c: In function ‘rwpng_read_image’:
rwpng.c:130:7: warning: passing argument 3 of ‘png_get_IHDR’ from incompatible pointer type
/usr/include/png.h:2300:1: note: expected ‘png_uint_32 *’ but argument is of type ‘ulg *’
rwpng.c:130:7: warning: passing argument 4 of ‘png_get_IHDR’ from incompatible pointer type
/usr/include/png.h:2300:1: note: expected ‘png_uint_32 *’ but argument is of type ‘ulg *’