Don't block threads in the png codec when PNG_SETJMP_SUPPORTED is not defined.
Don't block threads in the png codec when PNG_SETJMP_SUPPORTED is not defined.


Danack/ImageMagick,kwm81/ImageMagick,Danack/ImageMagick,UniQP/ImageMagick,UniQP/ImageMagick,Danack/ImageMagick,kwm81/ImageMagick,Danack/ImageMagick,Danack/ImageMagick,UniQP/ImageMagick,kwm81/ImageMagick,UniQP/ImageMagick,UniQP/ImageMagick,kwm81/ImageMagick,Danack/ImageMagick,UniQP/ImageMagick,kwm81/ImageMagick,kwm81/ImageMagick