Android: Always add standard include directories last

The logic added in commit v3.6.0-rc1~30^2 (Add a variable to specify
language-wide system include directories, 2016-05-24) to use
`CMAKE_<LANG>_STANDARD_INCLUDE_DIRECTORIES` incorrectly filters them by
`CMAKE_<LANG>_IMPLICIT_INCLUDE_DIRECTORIES`.  Rather than recognizing
this, commit v3.8.0-rc1~60^2 (Android: Pass sysroot include directory
explicitly, 2017-01-20) worked around the problem by incorrectly
removing `/usr/include` from `CMAKE_<LANG>_IMPLICIT_INCLUDE_DIRECTORIES`
so it worked in `CMAKE_<LANG>_STANDARD_INCLUDE_DIRECTORIES`.

By not filtering out `/usr/include` from user-specified include
directories, we allow the code

    include_directories(${CMAKE_SYSROOT}/usr/include)

to place the include directory too early on the command line.

Fix support for standard include directories to not be filtered by
implicit include directories, and do not remove `/usr/include` from the
list of implicit include directories for Android builds.  Add a test
case to verify that an explicit `/usr/include` is ignored in favor
of the standard directory at the end.

Fixes: #17059

1 files changed, 14 insertions, 0 deletions

diff --git a/Source/cmLocalGenerator.cxx b/Source/cmLocalGenerator.cxx
index 8e00303..5a062bc 100644
--- a/Source/cmLocalGenerator.cxx
+++ b/Source/cmLocalGenerator.cxx
@@ -916,6 +916,20 @@ void cmLocalGenerator::GetIncludeDirectories(std::vector<std::string>& dirs,
     }
   }
 
+  // Add standard include directories for this language.
+  // We do not filter out implicit directories here.
+  std::string const standardIncludesVar =
+    "CMAKE_" + lang + "_STANDARD_INCLUDE_DIRECTORIES";
+  std::string const standardIncludes =
+    this->Makefile->GetSafeDefinition(standardIncludesVar);
+  std::vector<std::string>::size_type const before = includes.size();
+  cmSystemTools::ExpandListArgument(standardIncludes, includes);
+  for (std::vector<std::string>::iterator i = includes.begin() + before;
+       i != includes.end(); ++i) {
+    cmSystemTools::ConvertToUnixSlashes(*i);
+    dirs.push_back(*i);
+  }
+
   for (std::vector<std::string>::const_iterator i = implicitDirs.begin();
        i != implicitDirs.end(); ++i) {
     if (std::find(includes.begin(), includes.end(), *i) != includes.end()) {