RocksDB on FreeBSD support

Summary:
This patch will update the Makefile and source code so that we can build RocksDB successfully on FreeBSD 10 and 11 (64-bit and 32-bit)
I have also encountered some problems when running tests on FreeBSD, I will try to fix them individually in different diffs

Notes:

  - FreeBSD uses clang as it's default compiler (http://lists.freebsd.org/pipermail/freebsd-current/2012-September/036480.html)
  - GNU C++ compiler have C++ 11 problems on FreeBSD (https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=193528)
  - make is not gmake on FreeBSD (http://www.khmere.com/freebsd_book/html/ch01.html)

Test Plan:
Using VMWare Fusion Create 4 VM machines (FreeBSD 11 64-bit, FreeBSD 11 32-bit, FreeBSD 10 64-bit, FreeBSD 10 32-bit)

  - pkg install git gmake gflags archivers/snappy
  - git clone https://github.com/facebook/rocksdb.git
  - apply this patch
  - setenv CXX c++
  - setenv CPATH /usr/local/include/
  - setenv LIBRARY_PATH  /usr/local/lib/
  - gmake db_bench
  - make sure compilation is successful and db_bench is running
  - gmake all
  - make sure compilation is successful

Reviewers: sdong, igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D33891

Makefile

@@ -10,7 +10,7 @@ CFLAGS += ${EXTRA_CFLAGS}
 CXXFLAGS += ${EXTRA_CXXFLAGS}
 LDFLAGS += $(EXTRA_LDFLAGS)
 MACHINE ?= $(shell uname -m)
-ARFLAGS = rs
+ARFLAGS = rsD
 
 ifneq ($(MAKECMDGOALS),dbg)
 OPT += -O2 -fno-omit-frame-pointer

Vagrantfile

@@ -13,4 +13,21 @@ Vagrant.configure("2") do |config|
     box.vm.box = "chef/centos-6.5"
   end
 
+  config.vm.define "FreeBSD10" do |box|
+    box.vm.guest = :freebsd
+    box.vm.box = "robin/freebsd-10"
+    # FreeBSD does not support 'mount_virtualbox_shared_folder', use NFS
+    box.vm.synced_folder ".", "/vagrant", :nfs => true, id: "vagrant-root"
+    box.vm.network "private_network", ip: "10.0.1.10"
+
+    # build everything after creating VM, skip using --no-provision
+    box.vm.provision "shell", inline: <<-SCRIPT
+      pkg install -y gmake clang35
+      export CXX=/usr/local/bin/clang++35
+      cd /vagrant
+      gmake clean
+      gmake all OPT=-g
+    SCRIPT
+  end
+
 end

build_tools/build_detect_platform

@@ -75,6 +75,10 @@ if test -z "$TARGET_OS"; then
     TARGET_OS=`uname -s`
 fi
 
+if test -z "$TARGET_ARCHITECTURE"; then
+    TARGET_ARCHITECTURE=`uname -m`
+fi
+
 if test -z "$CLANG_SCAN_BUILD"; then
     CLANG_SCAN_BUILD=scan-build
 fi
@@ -300,6 +304,9 @@ EOF
     fi
 fi
 
+# TODO(tec): Fix -Wshorten-64-to-32 errors on FreeBSD and enable the warning.
+# -Wshorten-64-to-32 breaks compilation on FreeBSD i386
+if ! [ "$TARGET_OS" = FreeBSD -a "$TARGET_ARCHITECTURE" = i386 ]; then
   # Test whether -Wshorten-64-to-32 is available
   $CXX $CFLAGS -x c++ - -o /dev/null -Wshorten-64-to-32 2>/dev/null  <<EOF
     int main() {}
@@ -307,6 +314,7 @@ EOF
   if [ "$?" = 0 ]; then
     COMMON_FLAGS="$COMMON_FLAGS -Wshorten-64-to-32"
   fi
+fi
 
 # shall we use HDFS?
 
@@ -324,6 +332,11 @@ if test "$USE_HDFS"; then
   JAVA_LDFLAGS="$JAVA_LDFLAGS $HDFS_LDFLAGS"
 fi
 
+if [ "$TARGET_OS" = FreeBSD -a "$TARGET_ARCHITECTURE" = i386 ]; then
+  # Intel SSE instructions breaks compilation on FreeBSD i386
+  unset USE_SSE
+fi
+
 if test "$USE_SSE"; then
   # if Intel SSE instruction set is supported, set USE_SSE=1
   COMMON_FLAGS="$COMMON_FLAGS -msse -msse4.2 "

port/port_posix.h

@@ -25,7 +25,11 @@
   #else
     #define PLATFORM_IS_LITTLE_ENDIAN false
   #endif
-#elif defined(OS_FREEBSD) || defined(OS_OPENBSD) || defined(OS_NETBSD) ||\
+#elif defined(OS_FREEBSD)
+  #include <sys/endian.h>
+  #include <sys/types.h>
+  #define PLATFORM_IS_LITTLE_ENDIAN (_BYTE_ORDER == _LITTLE_ENDIAN)
+#elif defined(OS_OPENBSD) || defined(OS_NETBSD) ||\
       defined(OS_DRAGONFLYBSD) || defined(OS_ANDROID)
   #include <sys/types.h>
   #include <sys/endian.h>

util/log_buffer.h

@@ -5,6 +5,7 @@
 
 #pragma once
 
+#include <sys/time.h>
 #include "rocksdb/env.h"
 #include "util/arena.h"
 #include "util/autovector.h"

util/xfunc.h

@@ -4,6 +4,7 @@
 //  of patent rights can be found in the PATENTS file in the same directory.
 #pragma once
 
+#include <cstdlib>
 #include <string>
 
 namespace rocksdb {