add install stuff for platform directory

Modules/CMakeLists.txt

@@ -1,4 +1,5 @@
 # just install the modules
+SUBDIRS(Platform)
 INSTALL_FILES(/share/CMake/Modules .*\\.cmake$)
 INSTALL_FILES(/share/CMake/Modules .*\\.cxx$)
 INSTALL_FILES(/share/CMake/Modules .*\\.in$)

Modules/Platform/CMakeLists.txt

@@ -0,0 +1,2 @@
+# just install the modules
+INSTALL_FILES(/share/CMake/Modules/Platform .*\\.cmake$)