Squashed 'src/leveldb/' changes from 330dd6235f..22f1e4a02f

22f1e4a02f Merge bitcoin-core/leveldb-subtree#32: fix macro HAVE_O_CLOEXEC when O_CLOEXEC not found
1eeb1cb879 fix macro HAVE_O_CLOEXEC when O_CLOEXEC not found

git-subtree-dir: src/leveldb
git-subtree-split: 22f1e4a02fd8e96090bb699a04c95c784aa88e74

Author: fanquake

util/env_posix.cc

@@ -49,7 +49,7 @@ constexpr const int kDefaultMmapLimit = (sizeof(void*) >= 8) ? 4096 : 0;
 int g_mmap_limit = kDefaultMmapLimit;
 
 // Common flags defined for all posix open operations
-#if defined(HAVE_O_CLOEXEC)
+#if HAVE_O_CLOEXEC
 constexpr const int kOpenBaseFlags = O_CLOEXEC;
 #else
 constexpr const int kOpenBaseFlags = 0;