[CMake] FIND_PACKAGE(SWIG) in cmake 1.8

[James Bigler]

I know this works in 2.0, but I need to know how I can fix the following code to 
work in 1.8 without breaking:

FIND_PACKAGE(SWIG)
IF (SWIG_FOUND)
   SET(MAIN_SUBDIRS ${MAIN_SUBDIRS} SwigInterface)
ENDIF (SWIG_FOUND)

I get errors from withing ccmake when swig isn't found saying this:

  CMake Error: SWIG_DIR is not set.  It must be set to the directory
  containing SWIGConfig.cmake so in order to use SWIG.

Is this a feature that is only found in 2.0?

Thanks,
James