ref: f0d4750ebc4d3fc5c6c0a2f36d14b59e8dd2d3fa dir: /GNUmakefile/
# GNU Make 3.x doesn't support the "!=" shell syntax, so here's an alternative PKG_CONFIG = pkg-config PNGFLAGS = $(shell ${PKG_CONFIG} --cflags libpng) include Makefile