libtiff: Update to version 4.6.0

libtiff: Update to version 4.6.0

- Update from version 4.5.1 to 4.6.0
- Update of rootfile
- Included options to disable static library and docs.
- The removed functionality mentioned in the changelog below was already mentioned in
   earlier version updates. As far as I could tell none of the functionality that has
   been removed is used in IPFire.
- Changelog
    4.6.0
      Major changes warning
	This version removes a big number of utilities that have suffered from lack of
	 maintenance over the years and were the source of various reported security
	 issues. See "Removed functionality" below for the list of removed utilities.
	 Starting with libtiff v4.6.0, the source code for most TIFF tools
	 (except tiffinfo, tiffdump, tiffcp and tiffset) was discontinued, due to the
	 lack of contributors able to address reported security issues. tiff2ps and
	 tiff2pdf source code has been moved in a unsupported category, no longer built
	 by default, but are still part of the the source distribution. Other retired
	 utilities are in a archive/ directory, only available in the libtiff git
	 repository. Issues related to unsupported and archived tools will no longer be
	 accepted in the libtiff bug tracker.
      Software configuration changes
	    TiffConfig.cmake.in: set TIFF_INCLUDE_DIR, TIFF_INCLUDE_DIRS and
	     TIFF_LIBRARIES for compatibility with FindTIFF.cmake as shipped by CMake
	     (fixes issue #589)
	    Update CMake and autoconf scripts to consistently update LibTIFF version
	     defines and references in various files when version definition in
	     configure.ac has been changed.
	        Move in tiffvers.h from libtiff source directory to libtiff build
		 directory.
	        Remove unused version information from tif_config.h
	        With every CMake build the version defines (e.g. 4.5.1) within tiffvers.h
		 are consistently updated from configure.ac. The version release-date is
		 taken from file RELEASE-DATE.
	        The files VERSION and RELEASE-DATE are only updated with a special CMake
		 target build: cmake --build . --target tiff_release.
	        For autotools, version information is updated from configure.ac with
		 ./autogen.sh. LIBTIFF_RELEASE_DATE is taken form file RELEASE-DATE.
	        ./configure generates tiffvers.h with the cached version information and
		 LIBTIFF_RELEASE_DATE.
	        "make release" updates tiffvers.h and VERSION file with cached version
		 info and RELEASE-DATE file and tiffves.h with the current date.
	    CMake: fix build with -Dstrip-chopping=off (fixes issue #600)
      Library changes
	New/improved functionalities:
	    Fix using __attribute__ libtiff with clang-for-windows
	Bug fixes:
	    WebP decoder: validate WebP blob width, height, band count against TIFF
	     parameters to avoid use of uninitialized variable, or decoding corrupted
	     content without explicit error (fixes issue #581, issue #582).
	    WebP codec: turn exact mode when creating lossless files to avoid altering
	     R,G,B values in areas where alpha=0
	     (https://github.com/OSGeo/gdal/issues/8038)
	    Fix TransferFunction writing of only two transfer functions.
	    TIFFReadDirectoryCheckOrder: avoid integer overflow. When it occurs, it
	     should be harmless in practice though
	     (https://gitlab.com/libtiff/libtiff/-/merge_requests/512)
	Documentation
	    TiffField functions documentation updated with return behaviour for not
	     defined tags and determination of write-/read-count size.
      Tools changes
	Removed functionality:
	    The following tools are no longer compiled and have been moved to
	     archive/tools:
	        fax2ps
	        fax2tiff
	        pal2rgb
	        ppm2tiff
	        raw2tiff
	        rgb2ycbcr
	        thumbnail
	        tiff2bw
	        tiff2rgba
	        tiffcmp
	        tiffcrop
	        tiffdither
	        tiffgt
	        tiffmedian
	    The following tools are no longer compiled by default: tiff2ps and tiff2pdf.
	     They have been moved to tools/unsupported. They can be built by setting
	     --enable-tools-unsupported for autoconf, or -Dtiff-tools-unsupported for
	     CMake, but as the name imply, they are no longer supported by upstream.
	     Packagers are suggested not to enable those options.
	    tiffcp: remove -i option (ignore errors), because almost all fuzzer issues
	     were consequential errors from ignored errors because of the "-i" option.
	Bug fixes:
	    tiffset: fix #597: warning: comparison of integer expressions of different
	     signedness. (fixes issue #597)
	    tiffcp: fix memory corruption (overflow) on hostile images (fixes issue #591)
	Test changes
	    Add missing test_write_read_tags.c and test_transferfunction_write_read.c in
	     tarball (fixes issue #585) and correct "long" issue.
	    Don't use "long" because can be int32_t or int64_t, depending on compiler
	     and system.
	Changes to contributed and unsupported tools
	    raw2tiff: fix integer overflow and bypass of the check (fixes issue #592)

Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>