1c1
< CFLAGS := -Wall -Wextra -Werror -std=c89 -pedantic -O2
---
> CFLAGS := -Wall -Wextra -std=c89 -pedantic -O2
3c3
< LIBPNG_FLAGS := $(shell pkg-config --cflags --libs libpng12)
---
> LIBPNG_FLAGS := $(shell pkg-config --cflags --libs libpng)