Ninja: Support embedding of CMake as subninja project

Add a `CMAKE_NINJA_OUTPUT_PATH_PREFIX` variable.  When it is set, CMake
generates a `build.ninja` file suitable for embedding into another ninja
project potentially generated by an alien generator.

1 files changed, 7 insertions, 0 deletions

diff --git a/Tests/RunCMake/Ninja/hello_with_greeting.c b/Tests/RunCMake/Ninja/hello_with_greeting.c
new file mode 100644
index 0000000..dbf90e3
--- /dev/null
+++ b/Tests/RunCMake/Ninja/hello_with_greeting.c
@@ -0,0 +1,7 @@
+#include <greeting.h>
+
+int main(void)
+{
+  greeting();
+  return 0;
+}