cmLocalGenerator: Clarify GetIncludeFlags signature

Make the `config` argument non-optional so all callers must be explicit.
Convert the path style argument to an enumeration to make its role clear
at call sites.

The path style argument is implemented by `ConvertToIncludeReference`,
which was introduced with the Ninja generator by commit 5b114c9bee
(Introduce a cmLocalGenerator::ConvertToIncludeReference function,
2011-09-07, v2.8.7~187^2~4).  Its only purpose is to allow the Ninja
generator to use relative paths in `-I` flags.  Add a comment explaining
this role.

1 files changed, 3 insertions, 3 deletions

diff --git a/Source/cmLocalNinjaGenerator.cxx b/Source/cmLocalNinjaGenerator.cxx
index 8ed411a..64ff579 100644
--- a/Source/cmLocalNinjaGenerator.cxx
+++ b/Source/cmLocalNinjaGenerator.cxx
@@ -202,10 +202,10 @@ cmGlobalNinjaGenerator* cmLocalNinjaGenerator::GetGlobalNinjaGenerator()
 // Virtual protected methods.
 
 std::string cmLocalNinjaGenerator::ConvertToIncludeReference(
-  std::string const& path, cmOutputConverter::OutputFormat format,
-  bool forceFullPaths)
+  std::string const& path, IncludePathStyle pathStyle,
+  cmOutputConverter::OutputFormat format)
 {
-  if (forceFullPaths) {
+  if (pathStyle == IncludePathStyle::Absolute) {
     return this->ConvertToOutputFormat(
       cmSystemTools::CollapseFullPath(path, this->GetCurrentBinaryDirectory()),
       format);