The :prologue-code in cmp:builder is now executed after cl_boot() and it can be lisp code.

src/cmp/cmpmain.lsp

@@ -261,8 +261,8 @@ void ~A(cl_object cblock)
 int
 main(int argc, char **argv)
 {
-	~A
 	cl_boot(argc, argv);
+	~A
 	read_VV(OBJNULL, ~A);
 	~A
 }")
@@ -275,9 +275,9 @@ WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdS
 {
 	char **argv;
 	int argc;
-	~A
 	ecl_get_commandline_args(&argc, &argv);
 	cl_boot(argc, argv);
+	~A
 	read_VV(OBJNULL, ~A);
 	~A
 }")
@@ -416,6 +416,22 @@ return 1;"
                             stream))
 		   (princ #\} stream)
 		   )))))
+  (cond ((null prologue-code)
+	 (setf prologue-code ""))
+	((stringp prologue-code)
+	 )
+	(t
+	 (with-standard-io-syntax
+	   (setq prologue-code
+		 (with-output-to-string (stream)
+		   (princ "{ const char *lisp_code = " stream)
+		   (wt-filtered-data (write-to-string prologue-code) stream)
+		   (princ ";
+cl_object output;
+si_select_package(make_simple_base_string(\"CL-USER\"));
+output = si_safe_eval(3, ecl_read_from_cstring(lisp_code), Cnil, OBJNULL);
+}" stream)
+		   )))))
   ;;
   ;; When a module is built out of several object files, we have to
   ;; create an additional object file that initializes those ones.