On Windows, the application manifest file can be linked with the
executable, to specify for example the requested privileges of the
application. On MSVC nmake, the manifest is already handled in
NmakeMakefileGenerator::writeBuildRulesPart, but it is not compatible
with MinGW. On MinGW, this manifest file has to be referenced in the
Rc File. This patch simply handles the existing variable
"QMAKE_MANIFEST" which defines the appropriate line RT_MANIFEST in
the RC file.
Task-number: QTBUG-42454
Change-Id: I921606e002ffe3801c537f30ac2365891f97d5c9
Reviewed-by: Joerg Bornemann <joerg.bornemann@theqtcompany.com>