Casts from std::string -> cmStdString were high on the list of things
taking up time. Avoid such implicit casts across function calls by just
using std::string everywhere.
The comment that the symbol name is too long is no longer relevant since
modern debuggers alias the templates anyways and the size is a
non-issue since the underlying methods are generated since it's
inherited.
Just enough to reach the BuildMacContentDirectory method and the
NeedRelinkBeforeInstall methods.
In the future, those methods can be moved to cmGeneratorTarget.
Refactoring in commit a2514f15 (Simplify cmNinjaTargetGenerator using
cmGeneratorTarget, 2012-03-13) accidentally removed mapping of .def file
paths through ConvertToNinjaPath (via GetSourceFilePath). Take the
ModuleDefinitionFile value from cmGeneratorTarget and map it correctly
through ConvertToNinjaPath.
In addition to generating cleaner paths in the ninja build files this
correctly links up references to a generated .def file with the custom
command output that produces it.
Generally these are only required in build statements, as Ninja wants
to be able to chop paths up. But it doesn't hurt to also try to use
them in command line arguments.