Merge remote-tracking branch 'remotes/artifex-local/master'

# Conflicts:
#	.gitmodules
#	thirdparty/curl
#	thirdparty/extract
#	thirdparty/freeglut
#	thirdparty/freetype
#	thirdparty/gumbo-parser
#	thirdparty/harfbuzz
#	thirdparty/jbig2dec
#	thirdparty/lcms2
#	thirdparty/leptonica
#	thirdparty/libpng
#	thirdparty/libtiff
#	thirdparty/mujs
#	thirdparty/openjpeg
#	thirdparty/tesseract
#	thirdparty/zlib