[CMake] trouble setting library output directoy

[Christopher Harvey]

Hi,
I've got a root directory, say /
and there is a CMakeLists.txt in it, that looks like this:
----------------
CMAKE_MINIMUM_REQUIRED(VERSION 2.6)
PROJECT(GlewMingW)
#SET(CMAKE_VERBOSE_MAKEFILE TRUE)
INCLUDE_DIRECTORIES(include)
ADD_LIBRARY(glew STATIC src/glew.c)
#ADD_EXECUTABLE(visualinfo src/visualinfo.c)
#ADD_EXECUTABLE(glewinfo src/glewinfo.c)
SET_TARGET_PROPERTIES(glew PROPERTIES
			   COMPILE_FLAGS -O3
			   LIBRARY_OUTPUT_DIRECTORY lib
	             )
#SET_TARGET_PROPERTIES(visualinfo PROPERTIES COMPILE_FLAGS -O3)
#SET_TARGET_PROPERTIES(glewinfo PROPERTIES COMPILE_FLAGS -O3)
#TARGET_LINK_LIBRARIES(glewinfo -glew opengl32 -mwindows)
--------------------

there is also a /lib directory with nothing in it.
The problem is then when I run cmake ./ it says that there are no
problems, and it compiles with ming32-make as well. The only thing is
that libglew.a appears in / rather than the /lib directory. I've
googled around but wasn't able to find an example that did what I
wanted it to do. Thanks for reading,
Chris.