Add support for cmake 3.7 (#660)

[termux-packages] / packages / openjpeg / openjpeg-tools.subpackage.sh

TERMUX_SUBPKG_INCLUDE="bin/"
TERMUX_SUBPKG_DESCRIPTION="Command-line tools using the JPEG 2000 library"
TERMUX_SUBPKG_DEPENDS="libtiff, littlecms, openjpeg"