diff --git a/hphp/runtime/base/program_functions.cpp b/hphp/runtime/base/program_functions.cpp
index e12e997cd..e86be5f4e 100644
--- a/hphp/runtime/base/program_functions.cpp
+++ b/hphp/runtime/base/program_functions.cpp
@@ -1300,7 +1300,7 @@ static void on_timeout(int sig, siginfo_t* info, void* context) {
 
 void hphp_process_init() {
   pthread_attr_t attr;
-#ifndef __APPLE__
+#ifdef _GNU_SOURCE
   pthread_getattr_np(pthread_self(), &attr);
 #else
   pthread_attr_init(&attr);
diff --git a/hphp/runtime/ext/ext_hotprofiler.cpp b/hphp/runtime/ext/ext_hotprofiler.cpp
index 7ecfdb81b..f28856288 100644
--- a/hphp/runtime/ext/ext_hotprofiler.cpp
+++ b/hphp/runtime/ext/ext_hotprofiler.cpp
@@ -27,32 +27,33 @@
 #include "hphp/util/cycles.h"
 
 #ifdef __FreeBSD__
-# include <sys/resource.h>
-# include <sys/cpuset.h>
-# define cpu_set_t cpuset_t
-# define SET_AFFINITY(pid, size, mask) \
+#include <sys/resource.h>
+#include <sys/param.h>
+#include <sys/cpuset.h>
+#define cpu_set_t cpuset_t
+#define SET_AFFINITY(pid, size, mask) \
            cpuset_setaffinity(CPU_LEVEL_WHICH, CPU_WHICH_TID, -1, size, mask)
-# define GET_AFFINITY(pid, size, mask) \
+#define GET_AFFINITY(pid, size, mask) \
            cpuset_getaffinity(CPU_LEVEL_WHICH, CPU_WHICH_TID, -1, size, mask)
-#elif __APPLE__
-# include <mach/mach_init.h>
-# include <mach/thread_policy.h>
-# include <mach/thread_act.h>
+#elif defined(__APPLE__)
+#include <mach/mach_init.h>
+#include <mach/thread_policy.h>
+#include <mach/thread_act.h>
 
-# define cpu_set_t thread_affinity_policy_data_t
-# define CPU_SET(cpu_id, new_mask) \
+#define cpu_set_t thread_affinity_policy_data_t
+#define CPU_SET(cpu_id, new_mask) \
         (*(new_mask)).affinity_tag = (cpu_id + 1)
-# define CPU_ZERO(new_mask)                 \
+#define CPU_ZERO(new_mask)                 \
         (*(new_mask)).affinity_tag = THREAD_AFFINITY_TAG_NULL
-# define GET_AFFINITY(pid, size, mask) \
+#define GET_AFFINITY(pid, size, mask) \
          (*(mask)).affinity_tag = THREAD_AFFINITY_TAG_NULL
-# define SET_AFFINITY(pid, size, mask)       \
+#define SET_AFFINITY(pid, size, mask)       \
         thread_policy_set(mach_thread_self(), THREAD_AFFINITY_POLICY, \
                           (int *)mask, THREAD_AFFINITY_POLICY_COUNT)
 #else
-# include <sched.h>
-# define SET_AFFINITY(pid, size, mask) sched_setaffinity(0, size, mask)
-# define GET_AFFINITY(pid, size, mask) sched_getaffinity(0, size, mask)
+#include <sched.h>
+#define SET_AFFINITY(pid, size, mask) sched_setaffinity(0, size, mask)
+#define GET_AFFINITY(pid, size, mask) sched_getaffinity(0, size, mask)
 #endif
 
 
diff --git a/hphp/runtime/ext/ext_posix.cpp b/hphp/runtime/ext/ext_posix.cpp
index c636882a9..75a9729c3 100644
--- a/hphp/runtime/ext/ext_posix.cpp
+++ b/hphp/runtime/ext/ext_posix.cpp
@@ -20,6 +20,9 @@
 #include <sys/times.h>
 #include <sys/utsname.h>
 #include <sys/types.h>
+#ifdef __FreeBSD__
+#include <sys/param.h>
+#endif
 #include <sys/time.h>
 #include <pwd.h>
 #include <memory>
@@ -421,7 +424,7 @@ Variant f_posix_uname() {
   ret.set(s_release,    String(u.release,    CopyString));
   ret.set(s_version,    String(u.version,    CopyString));
   ret.set(s_machine,    String(u.machine,    CopyString));
-#if defined(_GNU_SOURCE) && !defined(__APPLE__) && !defined(__FreeBSD__)
+#if defined(_GNU_SOURCE)
   ret.set(s_domainname, String(u.domainname, CopyString));
 #endif
   return ret;
diff --git a/hphp/runtime/vm/debug/dwarf.cpp b/hphp/runtime/vm/debug/dwarf.cpp
index 89572b373..4b24ce100 100644
--- a/hphp/runtime/vm/debug/dwarf.cpp
+++ b/hphp/runtime/vm/debug/dwarf.cpp
@@ -17,7 +17,7 @@
 
 #include <stdio.h>
 #include "debug.h"
-#ifndef __APPLE__
+#if !defined(__APPLE__) && !defined(__FreeBSD__)
 #include "hphp/runtime/vm/debug/elfwriter.h"
 #endif
 #include "hphp/runtime/vm/debug/gdb-jit.h"
@@ -36,7 +36,7 @@ namespace Debug {
 int g_dwarfCallback(char *name, int size, Dwarf_Unsigned type,
             Dwarf_Unsigned flags, Dwarf_Unsigned link, Dwarf_Unsigned info,
             Dwarf_Unsigned *sect_name_index, Dwarf_Ptr handle, int *error) {
-#ifndef __APPLE__
+#if !defined(__APPLE__) && !defined(__FreeBSD__)
   ElfWriter *e = reinterpret_cast<ElfWriter *>(handle);
   return e->dwarfCallback(name, size, type, flags, link, info);
 #else
@@ -221,7 +221,7 @@ void DwarfInfo::compactChunks() {
     m_dwarfChunks[j] = nullptr;
   }
   m_dwarfChunks[i] = chunk;
-#ifndef __APPLE__
+#if !defined(__APPLE__) && !defined(__FreeBSD__)
   // register compacted chunk with gdb
   ElfWriter e = ElfWriter(chunk);
 #endif
@@ -291,7 +291,7 @@ DwarfChunk* DwarfInfo::addTracelet(TCRange range, const char* name,
     f->m_chunk = chunk;
   }
 
-#ifndef __APPLE__
+#if !defined(__APPLE__) && !defined(__FreeBSD__)
   if (f->m_chunk->m_functions.size() >= RuntimeOption::EvalGdbSyncChunks) {
     ElfWriter e = ElfWriter(f->m_chunk);
   }
@@ -306,7 +306,7 @@ void DwarfInfo::syncChunks() {
   for (i = 0; i < m_dwarfChunks.size(); i++) {
     if (m_dwarfChunks[i] && !m_dwarfChunks[i]->isSynced()) {
       unregister_gdb_chunk(m_dwarfChunks[i]);
-#ifndef __APPLE__
+#if !defined(__APPLE__) && !defined(__FreeBSD__)
       ElfWriter e = ElfWriter(m_dwarfChunks[i]);
 #endif
     }
diff --git a/hphp/runtime/vm/jit/translator-x64.cpp b/hphp/runtime/vm/jit/translator-x64.cpp
index 28fce3ab4..d8b694e04 100644
--- a/hphp/runtime/vm/jit/translator-x64.cpp
+++ b/hphp/runtime/vm/jit/translator-x64.cpp
@@ -28,6 +28,9 @@
 #include <unwind.h>
 #include <unordered_set>
 #include <signal.h>
+#ifdef __FreeBSD__
+#include <sys/ucontext.h>
+#endif
 
 #ifdef __FreeBSD__
 #define RIP_REGISTER(v) (v).mc_rip
diff --git a/hphp/util/assertions.h b/hphp/util/assertions.h
index a6210ca9e..c09f08b79 100644
--- a/hphp/util/assertions.h
+++ b/hphp/util/assertions.h
@@ -86,7 +86,7 @@ inline void assert_fail(const char* e,
                         const char* file,
                         unsigned int line,
                         const char* func) {
-#if !defined(NDEBUG) && !defined(__APPLE__)
+#if !defined(NDEBUG) && defined(_GNU_SOURCE)
   __assert_fail(e, file, line, func);
 #else
   extern void impl_assert_fail(const char*,
diff --git a/hphp/util/compatibility.cpp b/hphp/util/compatibility.cpp
index 239c00ece..2bb5cec61 100644
--- a/hphp/util/compatibility.cpp
+++ b/hphp/util/compatibility.cpp
@@ -20,7 +20,7 @@
 namespace HPHP {
 ///////////////////////////////////////////////////////////////////////////////
 
-#if defined(__APPLE__)
+#if defined(__APPLE__) || defined(__FreeBSD__)
 char *strndup(const char* str, size_t len) {
   size_t str_len = strlen(str);
   if (len < str_len) {
@@ -54,7 +54,7 @@ int dprintf(int fd, const char *format, ...) {
 #endif
 
 int gettime(clockid_t which_clock, struct timespec *tp) {
-#if defined(__APPLE__)
+#if defined(__APPLE__) || defined(__FreeBSD__)
   // XXX: OSX doesn't support realtime so we ignore which_clock
   struct timeval tv;
   int ret = gettimeofday(&tv, nullptr);
diff --git a/hphp/util/compatibility.h b/hphp/util/compatibility.h
index fb3ba77d2..1475d2a0d 100644
--- a/hphp/util/compatibility.h
+++ b/hphp/util/compatibility.h
@@ -24,7 +24,7 @@ namespace HPHP {
 
 #define PHP_DIR_SEPARATOR '/'
 
-#if defined(__APPLE__)
+#if defined(__APPLE__) || defined(__FreeBSD__)
 char *strndup(const char* str, size_t len);
 int dprintf(int fd, const char *format, ...) ATTRIBUTE_PRINTF(2,3);
 typedef int clockid_t;
diff --git a/hphp/util/vdso.cpp b/hphp/util/vdso.cpp
index d60bcbeb3..10bf685e2 100644
--- a/hphp/util/vdso.cpp
+++ b/hphp/util/vdso.cpp
@@ -14,9 +14,9 @@
    +----------------------------------------------------------------------+
 */
 
-#define _GNU_SOURCE 1
 #include "hphp/util/vdso.h"
 
+#define _GNU_SOURCE 1
 #include <dlfcn.h>