toolchain: add a program for compiling ipc interface definitions

ifc can be used to compile .if files into self-contained header-only C
libraries, which can be used to send/receive messages that conform
to the described interface.

toolchain/ifc/status.h

@@ -0,0 +1,20 @@
+#ifndef IFC_STATUS_H_
+#define IFC_STATUS_H_
+
+enum status {
+	SUCCESS = 0,
+	ERR_EOF,
+	ERR_BAD_SYNTAX,
+	ERR_BAD_FORMAT,
+	ERR_BAD_STATE,
+	ERR_INVALID_VALUE,
+	ERR_INVALID_ARGUMENT,
+	ERR_NO_MEMORY,
+	ERR_NO_ENTRY,
+	ERR_NO_DATA,
+	ERR_NAME_EXISTS,
+	ERR_NOT_SUPPORTED,
+	ERR_INTERNAL_FAILURE,
+};
+
+#endif