Added X86 codegeneration interface and tests

runtime/runtime.c

@@ -0,0 +1,22 @@
+/* Runtime library */
+
+# include <stdio.h>
+
+/* Lread is an implementation of the "read" construct */
+extern int Lread () {
+  int result;
+
+  printf ("> "); 
+  fflush (stdout);
+  scanf  ("%d", &result);
+
+  return result;
+}
+
+/* Lwrite is an implementation of the "write" construct */
+extern int Lwrite (int n) {
+  printf ("%d\n", n);
+  fflush (stdout);
+
+  return 0;
+}