From 6f2d003bc5aeba3e4448a9cb20818e8b40b34dc7 Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Thu, 24 Apr 2014 10:49:57 +0000
Subject: [PATCH] From Mattias Helsing, "Seems I was only half right given what
 you asked for. CMP0017 only says that modules that are found and ran from
 cmake modules dir should prefer cmake-provided modules. find_package() and
 include() still look in CMAKE_MODULE_PATH first.

After some investigating I've come up with a proposal examplified in
the attached FindGDAL.cmake script. It simply calls the cmake provided
FindGDAL.cmake if it exists and returns if it succeeds in finding GDAL
using that, otherwise continue with our local cmake code.
Pro: Wont clutter our root CMakeLists.txt
Con: If we begin to write more advanced Findxxx modules (using
COMPONENTS, REQUIRED etc.) we may have to revise this scheme.
"
---
 CMakeModules/FindGDAL.cmake | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/CMakeModules/FindGDAL.cmake b/CMakeModules/FindGDAL.cmake
index 5006e6c72..7abccec53 100644
--- a/CMakeModules/FindGDAL.cmake
+++ b/CMakeModules/FindGDAL.cmake
@@ -19,6 +19,14 @@
 # This makes the presumption that you are include gdal.h like
 # #include "gdal.h"
 
+if(EXISTS ${CMAKE_ROOT}/Modules/FindGDAL.cmake)
+  include(${CMAKE_ROOT}/Modules/FindGDAL.cmake)
+
+  if(GDAL_FOUND)
+    return()
+  endif()
+endif()
+
 FIND_PATH(GDAL_INCLUDE_DIR gdal.h
   PATHS
   $ENV{GDAL_DIR}