diff --git a/src/mzscheme/gc2/newgc.c b/src/mzscheme/gc2/newgc.c
index 862837c137..4d1373befd 100644
--- a/src/mzscheme/gc2/newgc.c
+++ b/src/mzscheme/gc2/newgc.c
@@ -249,7 +249,7 @@ inline static void pagemap_set(PageMap page_maps1, void *p, mpage *value) {
 
   pos = PAGEMAP64_LEVEL1_BITS(p);
   page_maps2 = page_maps1[pos];
-  if (!page_maps) {
+  if (!page_maps2) {
     page_maps2 = (mpage ***)calloc(PAGEMAP64_LEVEL2_SIZE, sizeof(mpage **));
     page_maps1[pos] = page_maps2;
   }
diff --git a/src/mzscheme/gc2/platforms.h b/src/mzscheme/gc2/platforms.h
index 6b91d5cb10..a5868477e9 100644
--- a/src/mzscheme/gc2/platforms.h
+++ b/src/mzscheme/gc2/platforms.h
@@ -4,6 +4,14 @@
 # define inline _inline
 #endif
 
+#include "../mzconfig.h"
+
+#ifdef SIZEOF_LONG
+# if SIZEOF_LONG == 8
+#  define SIXTY_FOUR_BIT_INTEGERS
+# endif
+#endif
+
 #if defined(sparc) || defined(__sparc) || defined(__sparc__)
 /* Required for `double' operations: */
 # define GC_ALIGN_EIGHT