apply leveldb cygwin patch from http://code.google.com/p/leveldb/issues/detail?id=188

src/leveldb/build_detect_platform

@@ -68,6 +68,12 @@ if [ "$CXX" = "g++" ]; then
 fi
 
 case "$TARGET_OS" in
+    CYGWIN_*)
+		PLATFORM=OS_LINUX
+		COMMON_FLAGS="$MEMCMP_FLAG -lpthread -DOS_LINUX -DCYGWIN"
+		PLATFORM_LDFLAGS="-lpthread"
+		PORT_FILE=port/port_posix.cc
+		;;
     Darwin)
         PLATFORM=OS_MACOSX
         COMMON_FLAGS="$MEMCMP_FLAG -DOS_MACOSX"

src/leveldb/port/port_posix.h

@@ -55,7 +55,7 @@
 
 #if defined(OS_MACOSX) || defined(OS_SOLARIS) || defined(OS_FREEBSD) ||\
     defined(OS_NETBSD) || defined(OS_OPENBSD) || defined(OS_DRAGONFLYBSD) ||\
-    defined(OS_ANDROID) || defined(OS_HPUX)
+    defined(OS_ANDROID) || defined(OS_HPUX) || defined(CYGWIN)
 // Use fread/fwrite/fflush on platforms without _unlocked variants
 #define fread_unlocked fread
 #define fwrite_unlocked fwrite