diff --git a/boehm-gc/dbg_mlc.c b/boehm-gc/dbg_mlc.c
new file mode 100644
index 0000000000000000000000000000000000000000..6c4b2ba56b9447bfc555c43231edccd10bcaf4f2
--- /dev/null
+++ b/boehm-gc/dbg_mlc.c
@@ -0,0 +1,629 @@
+/* 
+ * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
+ * Copyright (c) 1991-1995 by Xerox Corporation.  All rights reserved.
+ * Copyright (c) 1997 by Silicon Graphics.  All rights reserved.
+ *
+ * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
+ * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
+ *
+ * Permission is hereby granted to use or copy this program
+ * for any purpose,  provided the above notices are retained on all copies.
+ * Permission to modify the code and to distribute modified code is granted,
+ * provided the above notices are retained, and a notice that the code was
+ * modified is included with the above copyright notice.
+ */
+/* Boehm, October 9, 1995 1:16 pm PDT */
+# include "gc_priv.h"
+
+/* Do we want to and know how to save the call stack at the time of	*/
+/* an allocation?  How much space do we want to use in each object?	*/
+
+# define START_FLAG ((word)0xfedcedcb)
+# define END_FLAG ((word)0xbcdecdef)
+	/* Stored both one past the end of user object, and one before	*/
+	/* the end of the object as seen by the allocator.		*/
+
+
+/* Object header */
+typedef struct {
+    char * oh_string;		/* object descriptor string	*/
+    word oh_int;		/* object descriptor integers	*/
+#   ifdef NEED_CALLINFO
+      struct callinfo oh_ci[NFRAMES];
+#   endif
+    word oh_sz;			/* Original malloc arg.		*/
+    word oh_sf;			/* start flag */
+} oh;
+/* The size of the above structure is assumed not to dealign things,	*/
+/* and to be a multiple of the word length.				*/
+
+#define DEBUG_BYTES (sizeof (oh) + sizeof (word))
+#undef ROUNDED_UP_WORDS
+#define ROUNDED_UP_WORDS(n) BYTES_TO_WORDS((n) + WORDS_TO_BYTES(1) - 1)
+
+
+#ifdef SAVE_CALL_CHAIN
+#   define ADD_CALL_CHAIN(base, ra) GC_save_callers(((oh *)(base)) -> oh_ci)
+#   define PRINT_CALL_CHAIN(base) GC_print_callers(((oh *)(base)) -> oh_ci)
+#else
+# ifdef GC_ADD_CALLER
+#   define ADD_CALL_CHAIN(base, ra) ((oh *)(base)) -> oh_ci[0].ci_pc = (ra)
+#   define PRINT_CALL_CHAIN(base) GC_print_callers(((oh *)(base)) -> oh_ci)
+# else
+#   define ADD_CALL_CHAIN(base, ra)
+#   define PRINT_CALL_CHAIN(base)
+# endif
+#endif
+
+/* Check whether object with base pointer p has debugging info	*/ 
+/* p is assumed to point to a legitimate object in our part	*/
+/* of the heap.							*/
+GC_bool GC_has_debug_info(p)
+ptr_t p;
+{
+    register oh * ohdr = (oh *)p;
+    register ptr_t body = (ptr_t)(ohdr + 1);
+    register word sz = GC_size((ptr_t) ohdr);
+    
+    if (HBLKPTR((ptr_t)ohdr) != HBLKPTR((ptr_t)body)
+        || sz < sizeof (oh)) {
+        return(FALSE);
+    }
+    if (ohdr -> oh_sz == sz) {
+    	/* Object may have had debug info, but has been deallocated	*/
+    	return(FALSE);
+    }
+    if (ohdr -> oh_sf == (START_FLAG ^ (word)body)) return(TRUE);
+    if (((word *)ohdr)[BYTES_TO_WORDS(sz)-1] == (END_FLAG ^ (word)body)) {
+        return(TRUE);
+    }
+    return(FALSE);
+}
+
+/* Store debugging info into p.  Return displaced pointer. */
+/* Assumes we don't hold allocation lock.		   */
+ptr_t GC_store_debug_info(p, sz, string, integer)
+register ptr_t p;	/* base pointer */
+word sz; 	/* bytes */
+char * string;
+word integer;
+{
+    register word * result = (word *)((oh *)p + 1);
+    DCL_LOCK_STATE;
+    
+    /* There is some argument that we should dissble signals here.	*/
+    /* But that's expensive.  And this way things should only appear	*/
+    /* inconsistent while we're in the handler.				*/
+    LOCK();
+    ((oh *)p) -> oh_string = string;
+    ((oh *)p) -> oh_int = integer;
+    ((oh *)p) -> oh_sz = sz;
+    ((oh *)p) -> oh_sf = START_FLAG ^ (word)result;
+    ((word *)p)[BYTES_TO_WORDS(GC_size(p))-1] =
+         result[ROUNDED_UP_WORDS(sz)] = END_FLAG ^ (word)result;
+    UNLOCK();
+    return((ptr_t)result);
+}
+
+/* Check the object with debugging info at p 		*/
+/* return NIL if it's OK.  Else return clobbered	*/
+/* address.						*/
+ptr_t GC_check_annotated_obj(ohdr)
+register oh * ohdr;
+{
+    register ptr_t body = (ptr_t)(ohdr + 1);
+    register word gc_sz = GC_size((ptr_t)ohdr);
+    if (ohdr -> oh_sz + DEBUG_BYTES > gc_sz) {
+        return((ptr_t)(&(ohdr -> oh_sz)));
+    }
+    if (ohdr -> oh_sf != (START_FLAG ^ (word)body)) {
+        return((ptr_t)(&(ohdr -> oh_sf)));
+    }
+    if (((word *)ohdr)[BYTES_TO_WORDS(gc_sz)-1] != (END_FLAG ^ (word)body)) {
+        return((ptr_t)((word *)ohdr + BYTES_TO_WORDS(gc_sz)-1));
+    }
+    if (((word *)body)[ROUNDED_UP_WORDS(ohdr -> oh_sz)]
+        != (END_FLAG ^ (word)body)) {
+        return((ptr_t)((word *)body + ROUNDED_UP_WORDS(ohdr -> oh_sz)));
+    }
+    return(0);
+}
+
+void GC_print_obj(p)
+ptr_t p;
+{
+    register oh * ohdr = (oh *)GC_base(p);
+    
+    GC_err_printf1("0x%lx (", (unsigned long)ohdr + sizeof(oh));
+    GC_err_puts(ohdr -> oh_string);
+    GC_err_printf2(":%ld, sz=%ld)\n", (unsigned long)(ohdr -> oh_int),
+        			      (unsigned long)(ohdr -> oh_sz));
+    PRINT_CALL_CHAIN(ohdr);
+}
+
+void GC_debug_print_heap_obj_proc(p)
+ptr_t p;
+{
+    if (GC_has_debug_info(p)) {
+	GC_print_obj(p);
+    } else {
+	GC_default_print_heap_obj_proc(p);
+    }
+}
+
+void GC_print_smashed_obj(p, clobbered_addr)
+ptr_t p, clobbered_addr;
+{
+    register oh * ohdr = (oh *)GC_base(p);
+    
+    GC_err_printf2("0x%lx in object at 0x%lx(", (unsigned long)clobbered_addr,
+    					        (unsigned long)p);
+    if (clobbered_addr <= (ptr_t)(&(ohdr -> oh_sz))
+        || ohdr -> oh_string == 0) {
+        GC_err_printf1("<smashed>, appr. sz = %ld)\n",
+        	       GC_size((ptr_t)ohdr) - DEBUG_BYTES);
+    } else {
+        if (ohdr -> oh_string[0] == '\0') {
+            GC_err_puts("EMPTY(smashed?)");
+        } else {
+            GC_err_puts(ohdr -> oh_string);
+        }
+        GC_err_printf2(":%ld, sz=%ld)\n", (unsigned long)(ohdr -> oh_int),
+        			          (unsigned long)(ohdr -> oh_sz));
+        PRINT_CALL_CHAIN(ohdr);
+    }
+}
+
+void GC_check_heap_proc();
+
+void GC_start_debugging()
+{
+    GC_check_heap = GC_check_heap_proc;
+    GC_print_heap_obj = GC_debug_print_heap_obj_proc;
+    GC_debugging_started = TRUE;
+    GC_register_displacement((word)sizeof(oh));
+}
+
+# if defined(__STDC__) || defined(__cplusplus)
+    void GC_debug_register_displacement(GC_word offset)
+# else
+    void GC_debug_register_displacement(offset) 
+    GC_word offset;
+# endif
+{
+    GC_register_displacement(offset);
+    GC_register_displacement((word)sizeof(oh) + offset);
+}
+
+# ifdef GC_ADD_CALLER
+#   define EXTRA_ARGS word ra, char * s, int i
+#   define OPT_RA ra,
+# else
+#   define EXTRA_ARGS char * s, int i
+#   define OPT_RA
+# endif
+
+# ifdef __STDC__
+    GC_PTR GC_debug_malloc(size_t lb, EXTRA_ARGS)
+# else
+    GC_PTR GC_debug_malloc(lb, s, i)
+    size_t lb;
+    char * s;
+    int i;
+#   ifdef GC_ADD_CALLER
+	--> GC_ADD_CALLER not implemented for K&R C
+#   endif
+# endif
+{
+    GC_PTR result = GC_malloc(lb + DEBUG_BYTES);
+    
+    if (result == 0) {
+        GC_err_printf1("GC_debug_malloc(%ld) returning NIL (",
+        	       (unsigned long) lb);
+        GC_err_puts(s);
+        GC_err_printf1(":%ld)\n", (unsigned long)i);
+        return(0);
+    }
+    if (!GC_debugging_started) {
+    	GC_start_debugging();
+    }
+    ADD_CALL_CHAIN(result, ra);
+    return (GC_store_debug_info(result, (word)lb, s, (word)i));
+}
+
+#ifdef STUBBORN_ALLOC
+# ifdef __STDC__
+    GC_PTR GC_debug_malloc_stubborn(size_t lb, EXTRA_ARGS)
+# else
+    GC_PTR GC_debug_malloc_stubborn(lb, s, i)
+    size_t lb;
+    char * s;
+    int i;
+# endif
+{
+    GC_PTR result = GC_malloc_stubborn(lb + DEBUG_BYTES);
+    
+    if (result == 0) {
+        GC_err_printf1("GC_debug_malloc(%ld) returning NIL (",
+        	       (unsigned long) lb);
+        GC_err_puts(s);
+        GC_err_printf1(":%ld)\n", (unsigned long)i);
+        return(0);
+    }
+    if (!GC_debugging_started) {
+    	GC_start_debugging();
+    }
+    ADD_CALL_CHAIN(result, ra);
+    return (GC_store_debug_info(result, (word)lb, s, (word)i));
+}
+
+void GC_debug_change_stubborn(p)
+GC_PTR p;
+{
+    register GC_PTR q = GC_base(p);
+    register hdr * hhdr;
+    
+    if (q == 0) {
+        GC_err_printf1("Bad argument: 0x%lx to GC_debug_change_stubborn\n",
+        	       (unsigned long) p);
+        ABORT("GC_debug_change_stubborn: bad arg");
+    }
+    hhdr = HDR(q);
+    if (hhdr -> hb_obj_kind != STUBBORN) {
+        GC_err_printf1("GC_debug_change_stubborn arg not stubborn: 0x%lx\n",
+        	       (unsigned long) p);
+        ABORT("GC_debug_change_stubborn: arg not stubborn");
+    }
+    GC_change_stubborn(q);
+}
+
+void GC_debug_end_stubborn_change(p)
+GC_PTR p;
+{
+    register GC_PTR q = GC_base(p);
+    register hdr * hhdr;
+    
+    if (q == 0) {
+        GC_err_printf1("Bad argument: 0x%lx to GC_debug_end_stubborn_change\n",
+        	       (unsigned long) p);
+        ABORT("GC_debug_end_stubborn_change: bad arg");
+    }
+    hhdr = HDR(q);
+    if (hhdr -> hb_obj_kind != STUBBORN) {
+        GC_err_printf1("debug_end_stubborn_change arg not stubborn: 0x%lx\n",
+        	       (unsigned long) p);
+        ABORT("GC_debug_end_stubborn_change: arg not stubborn");
+    }
+    GC_end_stubborn_change(q);
+}
+
+#endif /* STUBBORN_ALLOC */
+
+# ifdef __STDC__
+    GC_PTR GC_debug_malloc_atomic(size_t lb, EXTRA_ARGS)
+# else
+    GC_PTR GC_debug_malloc_atomic(lb, s, i)
+    size_t lb;
+    char * s;
+    int i;
+# endif
+{
+    GC_PTR result = GC_malloc_atomic(lb + DEBUG_BYTES);
+    
+    if (result == 0) {
+        GC_err_printf1("GC_debug_malloc_atomic(%ld) returning NIL (",
+        	      (unsigned long) lb);
+        GC_err_puts(s);
+        GC_err_printf1(":%ld)\n", (unsigned long)i);
+        return(0);
+    }
+    if (!GC_debugging_started) {
+        GC_start_debugging();
+    }
+    ADD_CALL_CHAIN(result, ra);
+    return (GC_store_debug_info(result, (word)lb, s, (word)i));
+}
+
+# ifdef __STDC__
+    GC_PTR GC_debug_malloc_uncollectable(size_t lb, EXTRA_ARGS)
+# else
+    GC_PTR GC_debug_malloc_uncollectable(lb, s, i)
+    size_t lb;
+    char * s;
+    int i;
+# endif
+{
+    GC_PTR result = GC_malloc_uncollectable(lb + DEBUG_BYTES);
+    
+    if (result == 0) {
+        GC_err_printf1("GC_debug_malloc_uncollectable(%ld) returning NIL (",
+        	      (unsigned long) lb);
+        GC_err_puts(s);
+        GC_err_printf1(":%ld)\n", (unsigned long)i);
+        return(0);
+    }
+    if (!GC_debugging_started) {
+        GC_start_debugging();
+    }
+    ADD_CALL_CHAIN(result, ra);
+    return (GC_store_debug_info(result, (word)lb, s, (word)i));
+}
+
+#ifdef ATOMIC_UNCOLLECTABLE
+# ifdef __STDC__
+    GC_PTR GC_debug_malloc_atomic_uncollectable(size_t lb, EXTRA_ARGS)
+# else
+    GC_PTR GC_debug_malloc_atomic_uncollectable(lb, s, i)
+    size_t lb;
+    char * s;
+    int i;
+# endif
+{
+    GC_PTR result = GC_malloc_atomic_uncollectable(lb + DEBUG_BYTES);
+    
+    if (result == 0) {
+        GC_err_printf1(
+		"GC_debug_malloc_atomic_uncollectable(%ld) returning NIL (",
+                (unsigned long) lb);
+        GC_err_puts(s);
+        GC_err_printf1(":%ld)\n", (unsigned long)i);
+        return(0);
+    }
+    if (!GC_debugging_started) {
+        GC_start_debugging();
+    }
+    ADD_CALL_CHAIN(result, ra);
+    return (GC_store_debug_info(result, (word)lb, s, (word)i));
+}
+#endif /* ATOMIC_UNCOLLECTABLE */
+
+# ifdef __STDC__
+    void GC_debug_free(GC_PTR p)
+# else
+    void GC_debug_free(p)
+    GC_PTR p;
+# endif
+{
+    register GC_PTR base = GC_base(p);
+    register ptr_t clobbered;
+    
+    if (base == 0) {
+        GC_err_printf1("Attempt to free invalid pointer %lx\n",
+        	       (unsigned long)p);
+        if (p != 0) ABORT("free(invalid pointer)");
+    }
+    if ((ptr_t)p - (ptr_t)base != sizeof(oh)) {
+        GC_err_printf1(
+        	  "GC_debug_free called on pointer %lx wo debugging info\n",
+        	  (unsigned long)p);
+    } else {
+      clobbered = GC_check_annotated_obj((oh *)base);
+      if (clobbered != 0) {
+        if (((oh *)base) -> oh_sz == GC_size(base)) {
+            GC_err_printf0(
+                  "GC_debug_free: found previously deallocated (?) object at ");
+        } else {
+            GC_err_printf0("GC_debug_free: found smashed object at ");
+        }
+        GC_print_smashed_obj(p, clobbered);
+      }
+      /* Invalidate size */
+      ((oh *)base) -> oh_sz = GC_size(base);
+    }
+#   ifdef FIND_LEAK
+        GC_free(base);
+#   else
+	{
+	    register hdr * hhdr = HDR(p);
+	    GC_bool uncollectable = FALSE;
+
+	    if (hhdr ->  hb_obj_kind == UNCOLLECTABLE) {
+		uncollectable = TRUE;
+	    }
+#	    ifdef ATOMIC_UNCOLLECTABLE
+		if (hhdr ->  hb_obj_kind == AUNCOLLECTABLE) {
+		    uncollectable = TRUE;
+		}
+#	    endif
+	    if (uncollectable) GC_free(base);
+	}
+#   endif
+}
+
+# ifdef __STDC__
+    GC_PTR GC_debug_realloc(GC_PTR p, size_t lb, EXTRA_ARGS)
+# else
+    GC_PTR GC_debug_realloc(p, lb, s, i)
+    GC_PTR p;
+    size_t lb;
+    char *s;
+    int i;
+# endif
+{
+    register GC_PTR base = GC_base(p);
+    register ptr_t clobbered;
+    register GC_PTR result;
+    register size_t copy_sz = lb;
+    register size_t old_sz;
+    register hdr * hhdr;
+    
+    if (p == 0) return(GC_debug_malloc(lb, OPT_RA s, i));
+    if (base == 0) {
+        GC_err_printf1(
+              "Attempt to reallocate invalid pointer %lx\n", (unsigned long)p);
+        ABORT("realloc(invalid pointer)");
+    }
+    if ((ptr_t)p - (ptr_t)base != sizeof(oh)) {
+        GC_err_printf1(
+        	"GC_debug_realloc called on pointer %lx wo debugging info\n",
+        	(unsigned long)p);
+        return(GC_realloc(p, lb));
+    }
+    hhdr = HDR(base);
+    switch (hhdr -> hb_obj_kind) {
+#    ifdef STUBBORN_ALLOC
+      case STUBBORN:
+        result = GC_debug_malloc_stubborn(lb, OPT_RA s, i);
+        break;
+#    endif
+      case NORMAL:
+        result = GC_debug_malloc(lb, OPT_RA s, i);
+        break;
+      case PTRFREE:
+        result = GC_debug_malloc_atomic(lb, OPT_RA s, i);
+        break;
+      case UNCOLLECTABLE:
+	result = GC_debug_malloc_uncollectable(lb, OPT_RA s, i);
+ 	break;
+#    ifdef ATOMIC_UNCOLLECTABLE
+      case AUNCOLLECTABLE:
+	result = GC_debug_malloc_atomic_uncollectable(lb, OPT_RA s, i);
+	break;
+#    endif
+      default:
+        GC_err_printf0("GC_debug_realloc: encountered bad kind\n");
+        ABORT("bad kind");
+    }
+    clobbered = GC_check_annotated_obj((oh *)base);
+    if (clobbered != 0) {
+        GC_err_printf0("GC_debug_realloc: found smashed object at ");
+        GC_print_smashed_obj(p, clobbered);
+    }
+    old_sz = ((oh *)base) -> oh_sz;
+    if (old_sz < copy_sz) copy_sz = old_sz;
+    if (result == 0) return(0);
+    BCOPY(p, result,  copy_sz);
+    GC_debug_free(p);
+    return(result);
+}
+
+/* Check all marked objects in the given block for validity */
+/*ARGSUSED*/
+void GC_check_heap_block(hbp, dummy)
+register struct hblk *hbp;	/* ptr to current heap block		*/
+word dummy;
+{
+    register struct hblkhdr * hhdr = HDR(hbp);
+    register word sz = hhdr -> hb_sz;
+    register int word_no;
+    register word *p, *plim;
+    
+    p = (word *)(hbp->hb_body);
+    word_no = HDR_WORDS;
+    if (sz > MAXOBJSZ) {
+	plim = p;
+    } else {
+    	plim = (word *)((((word)hbp) + HBLKSIZE) - WORDS_TO_BYTES(sz));
+    }
+    /* go through all words in block */
+	while( p <= plim ) {
+	    if( mark_bit_from_hdr(hhdr, word_no)
+	        && GC_has_debug_info((ptr_t)p)) {
+	        ptr_t clobbered = GC_check_annotated_obj((oh *)p);
+	        
+	        if (clobbered != 0) {
+	            GC_err_printf0(
+	                "GC_check_heap_block: found smashed object at ");
+        	    GC_print_smashed_obj((ptr_t)p, clobbered);
+	        }
+	    }
+	    word_no += sz;
+	    p += sz;
+	}
+}
+
+
+/* This assumes that all accessible objects are marked, and that	*/
+/* I hold the allocation lock.	Normally called by collector.		*/
+void GC_check_heap_proc()
+{
+#   ifndef SMALL_CONFIG
+	if (sizeof(oh) & (2 * sizeof(word) - 1) != 0) {
+	    ABORT("Alignment problem: object header has inappropriate size\n");
+	}
+#   endif
+    GC_apply_to_all_blocks(GC_check_heap_block, (word)0);
+}
+
+struct closure {
+    GC_finalization_proc cl_fn;
+    GC_PTR cl_data;
+};
+
+# ifdef __STDC__
+    void * GC_make_closure(GC_finalization_proc fn, void * data)
+# else
+    GC_PTR GC_make_closure(fn, data)
+    GC_finalization_proc fn;
+    GC_PTR data;
+# endif
+{
+    struct closure * result =
+    		(struct closure *) GC_malloc(sizeof (struct closure));
+    
+    result -> cl_fn = fn;
+    result -> cl_data = data;
+    return((GC_PTR)result);
+}
+
+# ifdef __STDC__
+    void GC_debug_invoke_finalizer(void * obj, void * data)
+# else
+    void GC_debug_invoke_finalizer(obj, data)
+    char * obj;
+    char * data;
+# endif
+{
+    register struct closure * cl = (struct closure *) data;
+    
+    (*(cl -> cl_fn))((GC_PTR)((char *)obj + sizeof(oh)), cl -> cl_data);
+} 
+
+
+# ifdef __STDC__
+    void GC_debug_register_finalizer(GC_PTR obj, GC_finalization_proc fn,
+    				     GC_PTR cd, GC_finalization_proc *ofn,
+				     GC_PTR *ocd)
+# else
+    void GC_debug_register_finalizer(obj, fn, cd, ofn, ocd)
+    GC_PTR obj;
+    GC_finalization_proc fn;
+    GC_PTR cd;
+    GC_finalization_proc *ofn;
+    GC_PTR *ocd;
+# endif
+{
+    ptr_t base = GC_base(obj);
+    if (0 == base || (ptr_t)obj - base != sizeof(oh)) {
+        GC_err_printf1(
+	    "GC_register_finalizer called with non-base-pointer 0x%lx\n",
+	    obj);
+    }
+    GC_register_finalizer(base, GC_debug_invoke_finalizer,
+    			  GC_make_closure(fn,cd), ofn, ocd);
+}
+
+# ifdef __STDC__
+    void GC_debug_register_finalizer_ignore_self
+    				    (GC_PTR obj, GC_finalization_proc fn,
+    				     GC_PTR cd, GC_finalization_proc *ofn,
+				     GC_PTR *ocd)
+# else
+    void GC_debug_register_finalizer_ignore_self
+    				    (obj, fn, cd, ofn, ocd)
+    GC_PTR obj;
+    GC_finalization_proc fn;
+    GC_PTR cd;
+    GC_finalization_proc *ofn;
+    GC_PTR *ocd;
+# endif
+{
+    ptr_t base = GC_base(obj);
+    if (0 == base || (ptr_t)obj - base != sizeof(oh)) {
+        GC_err_printf1(
+	    "GC_register_finalizer_ignore_self called with non-base-pointer 0x%lx\n",
+	    obj);
+    }
+    GC_register_finalizer_ignore_self(base, GC_debug_invoke_finalizer,
+    			  	      GC_make_closure(fn,cd), ofn, ocd);
+}