pngminus: Change license to MIT, etc.

Change the license to MIT.
Move the license text from the source files to a LICENSE file.
Move the change log from the source files to a CHANGES file.
Delete the Turbo C makefile and simplify the Linux makefile heavily.
Create explicitly named static and shared executables in the makefile.
Refresh the README file a bit from the twenty year old one.

Signed-off-by: Willem van Schaik <>
Signed-off-by: Cosmin Truta <>
10 files changed