Revert "Extend the cmake_policy command to get warnings from cmake code."

This reverts commit 5caf3e3055b31b528cec4eb31d2d0eb286c44e14.
Updates.
Merge topic 'qcc-id' into next

2845e208 Updates.
f99968b9 Revert "Extend the cmake_policy command to get warnings from cmake code."
Introduce QCC compiler id for that QNX platform compiler.

Introduce policy CMP0047 to control resetting the id for
compatibility.

De-duplicate content in the QNX platform file by including the GNU
one. QNX is a form of GNU platform.

Do not clear CMAKE_SHARED_LIBRARY_${lang}_FLAGS variables.  They
are populated again later by the Compiler/GNU.cmake file anyway.

Modify the CMAKE_CXX_COMPILE_OBJECT variable only when the QCC
compiler id is in use, and the language is CXX.  Use the QNX
recommended flag for QCC instead of the gcc compatible -x flag.

Populate new module files to handle system includes and depfiles
when using the QCC compiler.

Remove code which unsets the system include and depfiles related
variables.  When a GNU driver is used instead of the QCC one, the
appropriate flags will be used.  These variables were previously
cleared for lowest-common-denominator compatibility with both
drivers.
Merge topic 'qcc-id' into next

f3b08925 Introduce QCC compiler id for that QNX platform compiler.