Sebastian Holtermann authored Jan 25, 2019 and Brad King committed Jan 28, 2019

This patch strips the `stripImplicitDirs` and `appendAllImplicitDirs`
parameters from the `cmLocalGenerator::GetIncludeDirectories` method and makes
it a wrapper into the new `cmLocalGenerator::GetIncludeDirectoriesImplicit`
method.  `cmLocalGenerator::GetIncludeDirectoriesImplicit` is the renamed old
implementation of `cmLocalGenerator::GetIncludeDirectories` and still
accepts `stripImplicitDirs` and `appendAllImplicitDirs`.

The motivation is that there's only *one* case where
`cmLocalGenerator::GetIncludeDirectories` is called with the
`stripImplicitDirs` parameter being `false` (QtAutoGen), but many other places
where it is called using the `true` default value.

QtAutoGen is modified to use `cmLocalGenerator::GetIncludeDirectoriesImplicit`
directly.  In two use cases of `cmLocalGenerator::GetIncludeDirectories`
the manually set `true` value for `stripImplicitDirs` is removed.