IRSL: Skip libgfxoffload if no Intel C++ is used

`libgfxoffload` is only used and installed by the Intel C/C++ compilers
and will be unavailable if only Intel Fortran has been installed.

Fixes: #17550

Modules/InstallRequiredSystemLibraries.cmake

@@ -600,11 +600,14 @@ if(_IRSL_HAVE_Intel)
     if(_Intel_compiler_ver VERSION_LESS 18)
       list(APPEND __install_dirs "${_Intel_redistdir}/irml" "${_Intel_redistdir}/irml_c")
     endif()
-    foreach(__Intel_lib IN ITEMS cilkrts20.dll libchkp.dll libgfxoffload.dll libioffload_host.dll libirngmd.dll
+    foreach(__Intel_lib IN ITEMS cilkrts20.dll libchkp.dll libioffload_host.dll libirngmd.dll
       libmmd.dll libmmdd.dll libmpx.dll liboffload.dll svml_dispmd.dll)
 
       list(APPEND __install_libs "${_Intel_redistdir}/${__Intel_lib}")
     endforeach()
+    if(CMAKE_C_COMPILER_ID STREQUAL Intel OR CMAKE_CXX_COMPILER_ID STREQUAL Intel)
+      list(APPEND __install_libs "${_Intel_redistdir}/libgfxoffload.dll")
+    endif()
     if(CMAKE_Fortran_COMPILER_ID STREQUAL Intel)
       foreach(__Intel_lib IN ITEMS ifdlg100.dll libicaf.dll libifcoremd.dll libifcoremdd.dll libifcorert.dll libifcorertd.dll libifportmd.dll)
 
@@ -637,10 +640,10 @@ if(_IRSL_HAVE_Intel)
       endforeach()
     endif()
     if(_Intel_compiler_ver VERSION_GREATER_EQUAL 15)
-      foreach(__Intel_lib IN ITEMS libgfxoffload.so libistrconv.so)
-
-        list(APPEND __install_libs "${_Intel_redistdir}/${__Intel_lib}")
-      endforeach()
+      list(APPEND __install_libs "${_Intel_redistdir}/libistrconv.so")
+      if(CMAKE_C_COMPILER_ID STREQUAL Intel OR CMAKE_CXX_COMPILER_ID STREQUAL Intel)
+        list(APPEND __install_libs "${_Intel_redistdir}/libgfxoffload.so")
+      endif()
     endif()
     if(_Intel_compiler_ver VERSION_GREATER_EQUAL 16)
       foreach(__Intel_lib IN ITEMS libioffload_host.so libioffload_host.so.5 libioffload_target.so libioffload_target.so.5 libmpx.so offload_main)