Makefile: Split zlib and libpng

Split zlib stuff from libpng, removing the hard dependency on libpng to decompress VGZ lumps, also uncommented lines that was commented out in sdl/mixer_sound.c, for whatever reason. If someone compiles without zlib, then PNG support will be explicitly disabled also.

changed the description

I'm not sure if you ought to have made some of the changes in sdl/mixer_sound.c tbh, I'll elaborate in a bit using inline comments if I can..

added 2 commits

• 49cb1ffe - Restore deleted endif
• fc5d9696 - Fix DD compiling

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..aaaaand you did the #endif thing again in DD's code this time.

I fail to see the issue, honestly, it compiles just fine.

..Okay, that was a bit too quick of a comment, now I see the issue.

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• b812a6a4 - Really fix DD compiling this time.

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resolved all discussions

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• 233bf299 - Move the ifdef

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• 1c375330 - Move the ifdef below

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• def090c9 - Move the ifdef

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added 1 commit

• 232a7ae7 - Change order of the ifdef

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• 027e6e8e - Change win_snd.c also

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merged

mentioned in commit 1115f41f

mentioned in merge request !278 (merged)