ENH: Enable propagation of linker flags

This change allows customizing the linker flags at the superbuild level.
The motivation behind this modification was to enable the use of the
gold linker in 3D Slicer, as referenced in
Slicer/Slicer#7294, to expedite the linking
phase during the build process.

Co-authored-by: Jean-Christophe Fillion-Robin <[email protected]>

CMakeLists.txt

@@ -357,6 +357,25 @@ set(ADDITIONAL_CXX_FLAGS "" CACHE STRING "Additional CXX Flags")
 mark_as_advanced(ADDITIONAL_CXX_FLAGS)
 mark_as_superbuild(ADDITIONAL_CXX_FLAGS)
 
+#-----------------------------------------------------------------------------
+# Linker flags
+#
+# This section is adapted to enhance the build process by introducing the
+# possibility of customizing linker flags. This was added in connection with
+# enabling the gold linker in 3D Slicer, as outlined in PR:
+# https://github.com/Slicer/Slicer/pull/7294.
+#
+set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS}" CACHE STRING "Flags used by the linker" FORCE)
+set(CMAKE_MODULE_LINKER_FLAGS "${CMAKE_MODULE_LINKER_FLAGS}" CACHE STRING "Flags used by the linker (module)" FORCE)
+set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS}"  CACHE STRING "Flags used by the linker (shared)" FORCE)
+
+mark_as_superbuild(VARS
+  CMAKE_EXE_LINKER_FLAGS:STRING
+  CMAKE_MODULE_LINKER_FLAGS:STRING
+  CMAKE_SHARED_LINKER_FLAGS:STRING
+  ALL_PROJECTS
+)
+
 #-----------------------------------------------------------------------------
 # Set symbol visibility Flags
 #