Ninja: Add `$subdir/{test,install,package}` targets

With the Makefile generator one can use `cd $subdir; make install` to build and
install targets associated with a given subdirectory.  This is not possible to
do with the Ninja generator since there is only one `build.ninja` file at the
top of the build tree.  However, we can approximate it by allowing one to run
`ninja $subdir/install` at the top of the tree to build the targets in the
corresponding subdirectory and install them.

This also makes sense for `test`, `package`, and other GLOBAL_TARGET targets.
It was already done for `all` by commit v3.6.0-rc1~240^2~2 (Ninja: Add
`$subdir/all` targets, 2016-03-11).

1 files changed, 14 insertions, 3 deletions

diff --git a/Help/generator/Ninja.rst b/Help/generator/Ninja.rst
index d94e5f6..ef0e28b 100644
--- a/Help/generator/Ninja.rst
+++ b/Help/generator/Ninja.rst
@@ -7,6 +7,17 @@ A build.ninja file is generated into the build tree.  Recent versions
 of the ninja program can build the project through the "all" target.
 An "install" target is also provided.
 
-For each subdirectory ``sub/dir`` of the project an additional target
-named ``sub/dir/all`` is generated that depends on all targets required
-by that subdirectory.
+For each subdirectory ``sub/dir`` of the project, additional targets
+are generated:
+
+``sub/dir/all``
+  Depends on all targets required by the subdirectory.
+
+``sub/dir/install``
+  Runs the install step in the subdirectory, if any.
+
+``sub/dir/test``
+  Runs the test step in the subdirectory, if any.
+
+``sub/dir/package``
+  Runs the package step in the subdirectory, if any.