[cmake-developers] Patch for new warning caused by CMP0054

[Ben Boeckel]

On Tue, Nov 18, 2014 at 23:18:20 +0000, Fraser Hutchison wrote:
> -if(CMAKE_C_SIMULATE_ID STREQUAL "MSVC"
> -   OR CMAKE_CXX_SIMULATE_ID STREQUAL "MSVC"
> -   OR CMAKE_Fortran_SIMULATE_ID STREQUAL "MSVC"
> -   OR CMAKE_C_COMPILER_ID STREQUAL "MSVC"
> -   OR CMAKE_CXX_COMPILER_ID STREQUAL "MSVC"
> +if(CMAKE_C_SIMULATE_ID STREQUAL MSVC
> +   OR CMAKE_CXX_SIMULATE_ID STREQUAL MSVC
> +   OR CMAKE_Fortran_SIMULATE_ID STREQUAL MSVC
> +   OR CMAKE_C_COMPILER_ID STREQUAL MSVC
> +   OR CMAKE_CXX_COMPILER_ID STREQUAL MSVC

I think you misinterpreted the warning message. It is saying that with
OLD behavior MSVC will be dereferenced (which is bad here because we
want to use it as a string) and with NEW behavior, MSVC is just a string
(and a change in behavior, hence the warning). Given:

    CMAKE_CXX_SIMULATE_ID -> MSVC
    MSVC -> 1

This now does:

    "MSVC" STREQUAL "1"

In fact, this is what CMake will do with CMP0054 set to OLD *anyways*
and these are actual bugs (and always have been; the dequoting of the
left side was done by me in a massive sweep, but the right side issue
was missed). These should be changed to:

    "x${var}" STREQUAL "xMSVC"

Though, an easier fix may be to push_scope() and set CMP0054 to NEW in
these files.

--Ben