HPCC-10771 Add USE_SIGNED_CHAR and USE_UNSIGNED_CHAR parameters to build
process

Add new parameters to commonSetup.cmake

Signed-off-by: Attila Vamos <attila.vamos@gmail.com>
Merge pull request #5332 from AttilaVamos/HPCC-10771-improvement

HPCC-10771 Add USE_SIGNED_CHAR and USE_UNSIGNED_CHAR parameters to build process

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>