remove libraries we don't have

Index: adm/cmake/occt_csf.cmake
--- adm/cmake/occt_csf.cmake.orig
+++ adm/cmake/occt_csf.cmake
@@ -117,14 +117,14 @@ else()
     set (CSF_OpenGlLibs  "EGL GLESv2")
     set (CSF_androidlog  "log")
   elseif (UNIX)
-    set (CSF_ThreadLibs  "pthread rt stdc++")
+    set (CSF_ThreadLibs  "pthread stdc++")
     if (USE_GLES2)
       set (CSF_OpenGlLibs  "EGL GLESv2")
     else()
       set (CSF_OpenGlLibs  "GL")
     endif()
     set (CSF_XwLibs      "X11 Xext Xi")
-    set (CSF_dl          "dl")
+    set (CSF_dl          "")
     set (CSF_fontconfig  "fontconfig")
   endif()
 endif()