workaround missing xft/xinerama cmake detection on unix

CMakeLists.txt

@@ -334,6 +334,23 @@ if(ENABLE_FLTK)
       # required for system sounds (until cmake updates find_package(FLTK))
       list(APPEND FLTK_LIBRARIES "-framework AudioToolbox")
     endif(APPLE AND FLTK_VERSION EQUAL 1.3)
+    if(UNIX AND FLTK_CONFIG_SCRIPT)
+      # missing Xft/Xinerama (until cmake updates find_package(FLTK))
+      execute_process(COMMAND ${FLTK_CONFIG_SCRIPT} --ldflags
+                      OUTPUT_VARIABLE FLTK_LDFLAGS)
+      if(X11_Xft_FOUND)
+        string(REGEX MATCH ".*Xft.*" ${FLTK_LDFLAGS} FLTK_HAVE_XFT)
+        if(FLTK_HAVE_XFT)
+          list(APPEND FLTK_LIBRARIES ${X11_Xft_LIB})
+        endif(FLTK_HAVE_XFT)
+      endif(X11_Xft_FOUND)
+      if(X11_Xinerama_FOUND)
+        string(REGEX MATCH ".*Xinerama.*" ${FLTK_LDFLAGS} FLTK_HAVE_XINERAMA)
+        if(FLTK_HAVE_XINERAMA)
+          list(APPEND FLTK_LIBRARIES ${X11_Xinerama_LIB})
+        endif(FLTK_HAVE_XINERAMA)
+      endif(X11_Xinerama_FOUND)
+    endif(UNIX AND FLTK_CONFIG_SCRIPT)
   endif(FLTK_FOUND)
 elseif(ENABLE_QT)
   find_package(Qt4)