patch-src_Gui_CMakeLists.txt

--- src/Gui/CMakeLists.txt.orig	2019-03-15 18:36:43 UTC
+++ src/Gui/CMakeLists.txt
@@ -71,7 +71,7 @@ else(MSVC)
         FreeCADApp
         ${COIN3D_LIBRARIES}
         ${Boost_LIBRARIES}
-        ${OPENGL_gl_LIBRARY}
+        ${OPENGL_gl_LIBRARY} -L${CMAKE_INSTALL_PREFIX}/lib
         ${3DCONNEXION_LINKFLAGS}
     )
 endif(MSVC)