Code review comment for lp:~agateau/unity-2d/maverick-libunity2d

Why adding X11 to the root CMakeLists.txt?

=== modified file 'CMakeLists.txt'
--- CMakeLists.txt 2011-01-14 20:42:44 +0000
+++ CMakeLists.txt 2011-01-27 15:12:29 +0000
@@ -13,6 +13,7 @@
 # Dependencies
 include(FindPkgConfig)
 find_package(Qt4 REQUIRED)
+find_package(X11 REQUIRED)

 include_directories(
     ${CMAKE_BINARY_DIR}
@@ -22,9 +23,11 @@
     ${QT_QTDECLARATIVE_INCLUDE_DIR}
     ${QT_QTXML_INCLUDE_DIR}
     ${QT_QTGUI_INCLUDE_DIR}
+ ${X11_INCLUDE_DIR}
     )