bootloader heap: more detailed errors on out-of-memory

It's hard enough to debug bootloader code already, let's gather as much
info as we can from error messages.

Change-Id: I47dff402286625d1213caa36ae6ee8ecf707dfad
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3574
Reviewed-by: waddlesplash <[email protected]>

src/system/boot/loader/heap.cpp

@@ -464,7 +464,8 @@ malloc(size_t size)
 		return malloc_large(size);
 
 	if (size > sAvailable) {
-		dprintf("malloc(): Out of memory!\n");
+		dprintf("malloc(): Out of memory allocating a block of %ld bytes, "
+			"only %ld left!\n", size, sAvailable);
 		return NULL;
 	}
 
@@ -473,7 +474,8 @@ malloc(size_t size)
 
 	if (chunk == NULL) {
 		// could not find a free chunk as large as needed
-		dprintf("malloc(): Out of memory!\n");
+		dprintf("malloc(): Out of memory allocating a block of %ld bytes, "
+			"no free chunks!\n", size);
 		return NULL;
 	}