Fix SSE 4.2 checks.

CMake has "normal" and "cache" variables, and unexpected things happen
if you have a normal and a cache variable with the same name.
Apparently, check_c_compiler_flag() currently sets its result variable
as a cache variable, and set(), by default, sets it as a normal
variable.

This means that there are two different HAVE_SSE4_2 variables, and the
top-level CMakeLists.txt looks at the cache variable when it creates
config.h; this means that if the nmmintrin.h test fails, config.h still
says we have SSE 4.2.

Instead, use separate variables for the "compiler can be made to
generate SSE 4.2 code" test and the "nmmintr.h works" test; that way we
don't have to worry about normal vs.  cache variables (and don't have to
worry about CMake changing what type of variable particular
functions/macros set).

Change-Id: I618ad402b248f35fffd822974b6a569d4e5d6398
Reviewed-on: https://code.wireshark.org/review/7073
Reviewed-by: Guy Harris <guy@alum.mit.edu>

0 files changed, 0 insertions, 0 deletions