[libxml2] cmake: Install libxml.m4 on UNIX-like platforms

[Nick Wellnhofer <nwellnhof src gnome org>]

commit eab0ce8ff78908addc7c82b08eac4baf6d3ce4f4
Author: Daniel E <daniel engberg lists pyret net>
Date:   Wed Jul 13 21:47:37 2022 +0000

    cmake: Install libxml.m4 on UNIX-like platforms
    
    Install libxml.m4 to follow GNU Autotools more closely

 CMakeLists.txt | 4 ++++
 1 file changed, 4 insertions(+)
---
diff --git a/CMakeLists.txt b/CMakeLists.txt
index bf97b042..e3d7c935 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -677,6 +677,10 @@ endif()
 configure_file(xml2-config.in xml2-config @ONLY)
 install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/xml2-config DESTINATION ${CMAKE_INSTALL_BINDIR} COMPONENT 
development)
 
+if(UNIX)
+       install(FILES ${CMAKE_CURRENT_SOURCE_DIR}/libxml.m4 DESTINATION ${CMAKE_INSTALL_DATADIR}/aclocal)
+endif()
+
 set(XML_INCLUDEDIR "-I${CMAKE_INSTALL_FULL_INCLUDEDIR}/libxml2")
 set(XML_LIBDIR "-L${CMAKE_INSTALL_FULL_LIBDIR}")