Add support for sysprop description files to c++

From now on, a c++ shared library can be built only with adding
".sysprop" description file to srcs. Sysprop library generator will
automatically generate a .cpp and .h files, and the header file will be
exposed to any clients linking against the shared library. For the full
schema of description file, see system/tools/sysprop/sysprop.proto.

Bug: 80125326
Test: 1) write a .sysprop description file.
2) create cc_library_shared and add description file to srcs.
3) create another module, link against library of 2), include generated
header, and access generated sysprop functions
4) see compile succeeded.

Change-Id: I95005a0724aeb8f11a856b7aee92787a16a5374d
diff --git a/cc/library.go b/cc/library.go
index 9eb3f47..920292d 100644
--- a/cc/library.go
+++ b/cc/library.go
@@ -678,6 +678,14 @@
 		}
 	}
 
+	if library.baseCompiler.hasSrcExt(".sysprop") {
+		flags := []string{
+			"-I" + android.PathForModuleGen(ctx, "sysprop", "include").String(),
+		}
+		library.reexportFlags(flags)
+		library.reuseExportedFlags = append(library.reuseExportedFlags, flags...)
+	}
+
 	return out
 }