Compiler can compile simple nested expressions and function calls.

The generated code can be called from C, and values can be passed between.
diff --git a/src/lisp/plat/plat.h b/src/lisp/plat/plat.h
index 227e0d2..87544ba 100644
--- a/src/lisp/plat/plat.h
+++ b/src/lisp/plat/plat.h
@@ -2,6 +2,7 @@
 
 #include <stdint.h>
 #include <stddef.h>
+#include <dasm_proto.h>
 
 /* Platform specific definitions */
 
@@ -9,3 +10,5 @@
 void *malloc_aligned (size_t size);
 void *realloc_aligned (void *addr, size_t size);
 void free_aligned (void *addr);
+
+void *link (dasm_State **Dst);