Add the target_include_directories command.

This is a convenience API to populate the corresponding properties.

Tests/CMakeCommands/target_include_directories/consumer.cpp

@@ -0,0 +1,27 @@
+
+#include "common.h"
+#include "publicinclude.h"
+#include "interfaceinclude.h"
+#include "importedinterfaceinclude.h"
+
+#ifdef PRIVATEINCLUDE_DEFINE
+#error Unexpected PRIVATEINCLUDE_DEFINE
+#endif
+
+#ifndef PUBLICINCLUDE_DEFINE
+#error Expected PUBLICINCLUDE_DEFINE
+#endif
+
+#ifndef INTERFACEINCLUDE_DEFINE
+#error Expected INTERFACEINCLUDE_DEFINE
+#endif
+
+#ifndef IMPORTEDINTERFACEINCLUDE_DEFINE
+#error Expected IMPORTEDINTERFACEINCLUDE_DEFINE
+#endif
+
+#ifndef CURE_DEFINE
+#error Expected CURE_DEFINE
+#endif
+
+int main() { return 0; }