[CMake] Visual Studio 8 and warning levels

[Neal Meyer]

I'm having some trouble getting a clean way to set the warning level
in my projects with Visual Studio 2005.

When I try this
SET(CMAKE_C_WARNING_LEVEL 4)
SET(CMAKE_CXX_WARNING_LEVEL 4)

It seems to be ignored because the project files still have the
warning level set to 3.  I only want to turn up (or down) the warning
level for particular projects so I don't want to mess with the cache
variable.

I found this searching through old posts and it works, but it seems a
bit sloppy to have to do this when there is a simply way to just set
the Warning Level.

IF(CMAKE_CXX_FLAGS MATCHES "/W[0-4]")
     STRING(REGEX REPLACE "/W[0-4]" "/W4" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
ELSE(CMAKE_CXX_FLAGS MATCHES "/W[0-4]")
     SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /W4")
ENDIF(CMAKE_CXX_FLAGS MATCHES "/W[0-4]")

-Neal