[LyX/2.4.x] CMake: install adwaita/darkmode icons (#13224)

[Kornel Benko]

commit ffc3d958125ae80a75832b64f301456de178eca2
Author: Juergen Spitzmueller <spitz at lyx.org>
Date:   Tue Sep 9 10:43:25 2025 +0200

    CMake: install adwaita/darkmode icons (#13224)
    
    Kornel, please double-check!
---
 development/cmake/Install.cmake | 1 +
 1 file changed, 1 insertion(+)

diff --git a/development/cmake/Install.cmake b/development/cmake/Install.cmake
index 2ae1d43479..9571be994b 100755
--- a/development/cmake/Install.cmake
+++ b/development/cmake/Install.cmake
@@ -130,6 +130,7 @@ endforeach()
 
 foreach(_imgext "png" "svgz" "gif" "xpm")
   lyx_install("data" ${TOP_SRC_DIR}/lib images       "*.${_imgext}"      . adwaita bullets ipa classic oxygen)
+  lyx_install("data" ${TOP_SRC_DIR}/lib images/adwaita "*.${_imgext}"      . darkmode)
   lyx_install("data" ${TOP_SRC_DIR}/lib images/math  "*.${_imgext}"      . oxygen)
 endforeach()
 lyx_install("data" ${TOP_SRC_DIR}/lib        citeengines          *.citeengine .)