toolchain: replace ifc interface compiler with xpcg

xpcg is used to generate xpc interfaces

toolchain/xpcg/ctx.h

@@ -0,0 +1,18 @@
+#ifndef XPCG_CTX_H_
+#define XPCG_CTX_H_
+
+#include "type.h"
+
+struct ctx {
+	struct type ctx_builtin_types[TYPE_OTHER];
+};
+
+extern struct ctx *ctx_create(void);
+extern void ctx_destroy(struct ctx *ctx);
+
+extern const struct type *ctx_get_type(struct ctx *ctx, const char *name);
+extern const struct type *ctx_get_builtin_type(
+	struct ctx *ctx,
+	enum type_id id);
+
+#endif