[glom] cmake: Add and use FindGettextPO

[Murray Cumming <murrayc src gnome org>]

commit 81af2497716cb56500436860636360d759ba6dda
Author: Murray Cumming <murrayc murrayc com>
Date:   Mon Mar 14 20:02:40 2016 +0100

    cmake: Add and use FindGettextPO
    
    Copied from here:
    https://github.com/fluxer/kdelibs/blob/master/cmake/modules/FindGettextPO.cmake
    under the BSD license.

 CMakeLists.txt |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)
---
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 69864b6..ad1227e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -961,6 +961,11 @@ include_directories(${Boost_INCLUDE_DIR})
 target_link_libraries(glom ${Boost_PYTHON-PY34_LIBRARY})
 
 
+include(CMakeScripts/GlomFindGettextPO.cmake)
+include_directories(${GETTEXTPO_INCLUDE_DIR})
+target_link_libraries(glom ${GETTEXTPO_LIBRARY})
+
+
 # Let the C++ compiler find the #include files for our own source code:
 include_directories(
         ${CMAKE_CURRENT_SOURCE_DIR}