mkdir -p $(usr)
cd build/libpng-$(version_libpng) && \
CPPFLAGS=-I$(usr)/include LDFLAGS=-L$(usr)/lib ./configure --prefix=$(usr) $(configure_libpng) && \
mkdir -p $(usr)
cd build/libpng-$(version_libpng) && \
CPPFLAGS=-I$(usr)/include LDFLAGS=-L$(usr)/lib ./configure --prefix=$(usr) $(configure_libpng) && \