[gtk-doc/wip/tintou/gobj-args] cmake: Actually check if the LD_LIBRAY_PATH variable is defined

[Corentin Noël <corentinnoel src gnome org>]

commit 12b22ccb9c6a15dc0c4f6ae45f1e03c207415877
Author: Corentin Noël <corentin elementary io>
Date:   Fri Oct 5 14:40:31 2018 +0200

    cmake: Actually check if the LD_LIBRAY_PATH variable is defined

 buildsystems/cmake/GtkDocScanGObjWrapper.cmake | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)
---
diff --git a/buildsystems/cmake/GtkDocScanGObjWrapper.cmake b/buildsystems/cmake/GtkDocScanGObjWrapper.cmake
index 4ad7d2e..72a6663 100644
--- a/buildsystems/cmake/GtkDocScanGObjWrapper.cmake
+++ b/buildsystems/cmake/GtkDocScanGObjWrapper.cmake
@@ -37,11 +37,11 @@ foreach(_flag ${EXTRA_LDFLAGS} ${GLIB_LDFLAGS})
 endforeach(_flag)
 
 foreach(_flag ${EXTRA_LDPATH})
-    if(ENV{LD_LIBRARY_PATH})
+    if(DEFINED ENV{LD_LIBRARY_PATH})
         set(ENV{LD_LIBRARY_PATH} "$ENV{LD_LIBRARY_PATH}:\"${_flag}\"")
-    else(ENV{LD_LIBRARY_PATH})
-        set(ENV{LD_LIBRARY_PATH} "${_flag}")
-    endif(ENV{LD_LIBRARY_PATH})
+    else(DEFINED ENV{LD_LIBRARY_PATH})
+        set(ENV{LD_LIBRARY_PATH} "\"${_flag}\"")
+    endif(DEFINED ENV{LD_LIBRARY_PATH})
 endforeach(_flag)
 
 message(STATUS "Executing gtkdoc-scangobj with:")