expat: Update to version 2.4.9

expat: Update to version 2.4.9

- Update from version 2.4.8 to 2.4.9
- Update of rootfile
- Changelog
   Release 2.4.9 Tue September 20 2022
        Security fixes:
	       #629 #640  CVE-2022-40674 -- Heap use-after-free vulnerability in
	                    function doContent. Expected impact is denial of service
	                    or potentially arbitrary code execution.
        Bug fixes:
	       	    #634  MinGW: Fix mis-compilation for -D__USE_MINGW_ANSI_STDIO=0
	            #614  docs: Fix documentation on effect of switch XML_DTD on
	                    symbol visibility in doc/reference.html
        Other changes:
	            #638  MinGW: Make fix-xmltest-log.sh drop more Wine bug output
	       #596 #625  Autotools: Sync CMake templates with CMake 3.22
	            #608  CMake: Migrate from use of CMAKE_*_POSTFIX to
	                    dedicated variables EXPAT_*_POSTFIX to stop affecting
	                    other projects
	       #597 #599  Windows|CMake: Add missing -DXML_STATIC to test runners
	                    and fuzzers
	       #512 #621  Windows|CMake: Render .def file from a template to fix
	                    linking with -DEXPAT_DTD=OFF and/or -DEXPAT_ATTR_INFO=ON
	       #611 #621  MinGW|CMake: Apply MSVC .def file when linking
	       #622 #624  MinGW|CMake: Sync library name with GNU Autotools,
	                    i.e. produce libexpat-1.dll rather than libexpat.dll
	                    by default.  Filename libexpat.dll.a is unaffected.
	            #632  MinGW|CMake: Set missing variable CMAKE_RC_COMPILER in
	                    toolchain file "cmake/mingw-toolchain.cmake" to avoid
	                    error "windres: Command not found" on e.g. Ubuntu 20.04
	       #597 #627  CMake: Unify inconsistent use of set() and option() in
	                    context of public build time options to take need for
	                    set(.. FORCE) in projects using Expat by means of
	                    add_subdirectory(..) off Expat's users' shoulders
	       #626 #641  Stop exporting API symbols when building a static library
	            #644  Resolve use of deprecated "fgrep" by "grep -F"
	            #620  CMake: Make documentation on variables a bit more consistent
	            #636  CMake: Drop leading whitespace from a #cmakedefine line in
	                    file expat_config.h.cmake
	            #594  xmlwf: Fix harmless variable mix-up in function nsattcmp
	  #592 #593 #610  Address Cppcheck warnings
	            #643  Address Clang 15 compiler warnings
	       #642 #644  Version info bumped from 9:8:8 to 9:9:8;
	                    see https://verbump.de/ for what these numbers do
        Infrastructure:
	       #597 #598  CI: Windows: Start covering MSVC 2022
	            #619  CI: macOS: Migrate off deprecated macOS 10.15
	            #632  CI: Linux: Make migration off deprecated Ubuntu 18.04 work
	            #643  CI: Upgrade Clang from 14 to 15
	            #637  apply-clang-format.sh: Add support for BSD find
	            #633  coverage.sh: Exclude MinGW headers
		    #635  coverage.sh: Fix name collision for -funsigned-char

Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>
Reviewed-by: Peter Müller <peter.mueller@ipfire.org>