Fix build in MXE (M cross environment)
Fix build in MXE (M cross environment)

Add "cmake_policy(SET CMP0017 NEW)" to CMakeLists.txt

$ cmake --help-policy CMP0017

> Starting with CMake 2.8.4, if a cmake-module shipped with CMake (i.e.
> located in the CMake module directory) calls include() or
> find_package(), the files located in the the CMake module directory
> are preferred over the files in CMAKE_MODULE_PATH.  This makes sure
> that the modules belonging to CMake always get those files included
> which they expect, and against which they were developed and tested.
> In call other cases, the files found in CMAKE_MODULE_PATH still take
> precedence over the ones in the CMake module directory.  The OLD
> behaviour is to always prefer files from CMAKE_MODULE_PATH over files
> from the CMake modules directory.

Error message:

CMake Error at /usr/share/cmake-2.8/Modules/FindPackageHandleStandardArgs.cmake:97 (MESSAGE):
  Could NOT find PkgConfig (missing: PKG_CONFIG_EXECUTABLE) (found version
  "0.28")
Call Stack (most recent call first):
  /usr/share/cmake-2.8/Modules/FindPackageHandleStandardArgs.cmake:288 (_FPHSA_FAILURE_MESSAGE)
  /usr/share/cmake-2.8/Modules/FindPkgConfig.cmake:102 (find_package_handle_standard_args)
  /mxe/src/cmake/FindTIFF.cmake:5 (find_package)
  /usr/share/cmake-2.8/Modules/Qt4ConfigDependentSettings.cmake:86 (find_package)
  /usr/share/cmake-2.8/Modules/FindQt4.cmake:1053 (INCLUDE)
  CMakeLists.txt:336 (find_package)

See https://github.com/mxe/mxe/pull/800
See https://github.com/mxe/mxe/issues/734

cascheberg/pcl,wgapl/pcl,KevenRing/vlp,ipa-rmb/pcl,Tabjones/pcl,krips89/pcl_newfeatures,kanster/pcl,mikhail-matrosov/pcl,krips89/pcl_newfeatures,KevenRing/pcl,KevenRing/pcl,ipa-rmb/pcl,ipa-rmb/pcl,cascheberg/pcl,shyamalschandra/pcl,cascheberg/pcl,raydtang/pcl,ipa-rmb/pcl,mikhail-matrosov/pcl,Tabjones/pcl,MMiknis/pcl,nikste/pcl,stfuchs/pcl,KevenRing/vlp,nikste/pcl,wgapl/pcl,stfuchs/pcl,nikste/pcl,KevenRing/vlp,MMiknis/pcl,drmateo/pcl,damienjadeduff/pcl,stefanbuettner/pcl,damienjadeduff/pcl,DaikiMaekawa/pcl,LZRS/pcl,ipa-rmb/pcl,wgapl/pcl,chenxingzhe/pcl,chenxingzhe/pcl,shangwuhencc/pcl,kanster/pcl,chenxingzhe/pcl,stefanbuettner/pcl,shangwuhencc/pcl,krips89/pcl_newfeatures,mikhail-matrosov/pcl,damienjadeduff/pcl,mikhail-matrosov/pcl,kanster/pcl,stfuchs/pcl,wgapl/pcl,LZRS/pcl,DaikiMaekawa/pcl,damienjadeduff/pcl,Tabjones/pcl,raydtang/pcl,raydtang/pcl,Tabjones/pcl,stefanbuettner/pcl,KevenRing/pcl,KevenRing/pcl,raydtang/pcl,lebronzhang/pcl,mikhail-matrosov/pcl,kanster/pcl,nikste/pcl,chenxingzhe/pcl,KevenRing/vlp,LZRS/pcl,lebronzhang/pcl,LZRS/pcl,shyamalschandra/pcl,damienjadeduff/pcl,krips89/pcl_newfeatures,DaikiMaekawa/pcl,raydtang/pcl,DaikiMaekawa/pcl,cascheberg/pcl,lebronzhang/pcl,wgapl/pcl,stefanbuettner/pcl,chenxingzhe/pcl,nikste/pcl,MMiknis/pcl,shyamalschandra/pcl,lebronzhang/pcl,drmateo/pcl,DaikiMaekawa/pcl,krips89/pcl_newfeatures,Tabjones/pcl,lebronzhang/pcl,shangwuhencc/pcl,MMiknis/pcl,KevenRing/pcl,cascheberg/pcl,stefanbuettner/pcl,shyamalschandra/pcl,drmateo/pcl,shangwuhencc/pcl,MMiknis/pcl,KevenRing/vlp,stfuchs/pcl,LZRS/pcl,drmateo/pcl,drmateo/pcl,kanster/pcl,shyamalschandra/pcl,shangwuhencc/pcl,stfuchs/pcl