From 0b200abe6338c6f3074d1c25734344a492970756 Mon Sep 17 00:00:00 2001
From: Matthew Flatt <mflatt@racket-lang.org>
Date: Sat, 1 Nov 2014 14:04:49 -0600
Subject: [PATCH] unbreak GC for Linux and some other Unix variants

Corrects another problem with cceda78374.
---
 racket/src/racket/gc2/vm.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/racket/src/racket/gc2/vm.c b/racket/src/racket/gc2/vm.c
index 55d36b3e90..f5f3b05990 100644
--- a/racket/src/racket/gc2/vm.c
+++ b/racket/src/racket/gc2/vm.c
@@ -20,7 +20,7 @@ enum {
 /* No block cache or alloc cache */
 #elif defined(OSKIT)
 # define OS_ALLOCATOR_NEEDS_ALIGNMENT
-#elif defined(MZ_USE_PLACES) && defined(PREFER_MMAP_LARGE_BLOCKS)
+#elif defined(MZ_USE_PLACES) || defined(PREFER_MMAP_LARGE_BLOCKS)
 # define USE_BLOCK_CACHE
 #else
 # define USE_ALLOC_CACHE
@@ -133,18 +133,21 @@ static void *mmu_alloc_page(MMU* mmu, size_t len, size_t alignment, int dirty, i
   mmu_assert_os_page_aligned(mmu, len);
 #ifdef USE_BLOCK_CACHE
   return block_cache_alloc_page(mmu->block_cache, len, alignment, dirty, type, expect_mprotect, src_block, &mmu->memory_allocated);
-#elif defined(USE_ALLOC_CACHE)
+#else
+  *src_block = NULL;
+# if defined(USE_ALLOC_CACHE)
   /* len = mmu_round_up_to_os_page_size(mmu, len); */
   {
     AllocCacheBlock *alloc_cache = mmu->alloc_caches[!!expect_mprotect];
     return alloc_cache_alloc_page(alloc_cache, len, alignment, dirty, &mmu->memory_allocated);
   }
-#else
+# else
   mmu->memory_allocated += len;
-# ifdef OS_ALLOCATOR_NEEDS_ALIGNMENT
+#  ifdef OS_ALLOCATOR_NEEDS_ALIGNMENT
   return os_alloc_aligned_pages(len, alignment, dirty);
-#else
+#  else
   return os_alloc_pages(len);
+#  endif
 # endif
 #endif
 }