--- core/clingutils/CMakeLists.txt.orig	2024-04-12 17:58:43 UTC
+++ core/clingutils/CMakeLists.txt
@@ -123,6 +123,20 @@ if (runtime_cxxmodules)
   if (CMAKE_SYSTEM_NAME MATCHES Darwin AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 15.0.0.15000309)
     set(custom_modulemaps ${custom_modulemaps} std_darwin.modulemap)
   endif()
+  #[[
+  FreeBSD port maintainer note:
+  Related to upstream PR https://github.com/root-project/root/pull/14920.
+  Depending on a given system's version of LLVM, the standard library module.modulemap file
+  distributed with the OS might cause ROOT to fail to build, because the module.modulemap
+  file needs patching.
+  The port patch removes the implicit use of the system's module.modulemap file and applies,
+  explicitly, the same module.modulemap file - with modifications, if needed.
+  The (modified) module.modulemap file is provided by the port in
+  ${PATCHDIR}/interpreter-cling-include-cling-std__fbsd${OSREL}.modulemap.
+  ]]#
+  if (CMAKE_SYSTEM_NAME MATCHES FreeBSD)
+    set(custom_modulemaps ${custom_modulemaps} std_fbsd.modulemap)
+  endif()
 
   if (NOT libcxx)
     if (MSVC)