Add include directory to library targets
Add include directory to library targets

When using zopfli as a subproject, users can do:

add_subdirectory(zopfli)

target_link_libraries(my_target libzopfli)

google/zopfli,google/zopfli,unknownbrackets/maxcso,JayXon/zopfli,unknownbrackets/maxcso,JayXon/zopfli,PKRoma/zopfli,PKRoma/zopfli,unknownbrackets/maxcso,PKRoma/zopfli,unknownbrackets/maxcso,unknownbrackets/maxcso,google/zopfli,ImageOptim/zopfli,pornel/google-zopfli,ImageOptim/zopfli,unknownbrackets/maxcso,pornel/google-zopfli,unknownbrackets/maxcso