Try to fix FindX11

Modules/FindX11.cmake

@@ -24,6 +24,35 @@ IF (UNIX)
     /opt/graphics/OpenGL/include
   )
 
+  FIND_PATH(CMAKE_Xlib_INCLUDE_PATH X11/Xlib.h
+    /usr/include 
+    /usr/local/include 
+    /usr/openwin/include 
+    /usr/openwin/share/include 
+    /usr/X11R6/include 
+    /usr/include/X11
+    /opt/graphics/OpenGL/include
+  )
+
+  FIND_PATH(CMAKE_Xutil_INCLUDE_PATH X11/Xutil.h
+    /usr/include 
+    /usr/local/include 
+    /usr/openwin/include 
+    /usr/openwin/share/include 
+    /usr/X11R6/include 
+    /usr/include/X11
+    /opt/graphics/OpenGL/include
+  )
+
+  IF(CMAKE_X11_INCLUDE_PATH)
+    SET(CMAKE_X11_INCLUDES "${CMAKE_X11_INCLUDES};${CMAKE_X11_INCLUDE_PATH}")
+  ENDIF(CMAKE_X11_INCLUDE_PATH)
+  IF(CMAKE_Xlib_INCLUDE_PATH)
+    SET(CMAKE_X11_INCLUDES "${CMAKE_X11_INCLUDES};${CMAKE_Xlib_INCLUDE_PATH}")
+  ENDIF(CMAKE_Xlib_INCLUDE_PATH)
+  IF(CMAKE_Xutil_INCLUDE_PATH)
+    SET(CMAKE_X11_INCLUDES "${CMAKE_X11_INCLUDES};${CMAKE_Xutil_INCLUDE_PATH}")
+  ENDIF(CMAKE_Xutil_INCLUDE_PATH)
 
   FIND_LIBRARY(CMAKE_X11_LIBDIR X11
     /usr/lib 

Tests/X11/CMakeLists.txt

@@ -4,7 +4,11 @@ PROJECT (X11 C)
 INCLUDE (${CMAKE_ROOT}/Modules/FindX11.cmake)
 
 IF(CMAKE_HAS_X)
-  INCLUDE_DIRECTORIES(${CMAKE_X_CFLAGS})
+  IF(CMAKE_X_CFLAGS)
+    SET(CMAKE_C_FLAGS "${CMAKE_X_CFLAGS} ${CMAKE_C_FLAGS}")
+  ENDIF(CMAKE_X_CFLAGS)
+
+  INCLUDE_DIRECTORIES(${CMAKE_X11_INCLUDES})
   ADD_DEFINITIONS(-DCMAKE_HAS_X)
 ENDIF(CMAKE_HAS_X)