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Warning (mostly harmless): No library found for -lpng
PNG: building independently
PNG: Generic: includes not found - libraries not found
PNG: v1.6: includes not found - libraries not found
PNG: v1.5: includes not found - libraries not found
PNG: v1.4: includes not found - libraries not found
PNG: v1.2: includes not found - libraries not found
PNG: v1.0: includes not found - libraries not found
PNG: base (+libz): includes not found - libraries not found
PNG: v1.6 (+libz): includes not found - libraries not found
PNG: v1.5 (+libz): includes not found - libraries not found
PNG: v1.4 (+libz): includes not found - libraries not found
PNG: v1.2 (+libz): includes not found - libraries not found
PNG: v1.0 (+libz): includes not found - libraries not found
PNG: Checking if the compiler can find them on its own