Allow replacing the object cache with the guarded heap.

This allows to use the debug features of the guarded heap also on
allocations made through the object cache API. This is obivously
horrible for performance and uses up huge amounts of memory, so the
initial and grow sizes are adjusted accordingly.

Note that this is a rather simple hack, using the object_cache pointer
to transport the allocation size. The alignment is neglected completely.

headers/private/kernel/heap.h

@@ -13,6 +13,15 @@
 #include "kernel_debug_config.h"
 
 
+#if USE_GUARDED_HEAP_FOR_MALLOC && USE_GUARDED_HEAP_FOR_OBJECT_CACHE
+
+// This requires a lot of up-front memory to boot at all...
+#define INITIAL_HEAP_SIZE			128 * 1024 * 1024
+// ... and a lot of reserves to keep running.
+#define HEAP_GROW_SIZE				128 * 1024 * 1024
+
+#else // USE_GUARDED_HEAP_FOR_MALLOC && USE_GUARDED_HEAP_FOR_OBJECT_CACHE
+
 // allocate 16MB initial heap for the kernel
 #define INITIAL_HEAP_SIZE			16 * 1024 * 1024
 // grow by another 4MB each time the heap runs out of memory
@@ -22,6 +31,8 @@
 // use areas for allocations bigger than 1MB
 #define HEAP_AREA_USE_THRESHOLD		1 * 1024 * 1024
 
+#endif // !(USE_GUARDED_HEAP_FOR_MALLOC && USE_GUARDED_HEAP_FOR_OBJECT_CACHE)
+
 
 // allocation/deallocation flags for {malloc,free}_etc()
 #define HEAP_DONT_WAIT_FOR_MEMORY		0x01