Switch folly to using a submodule instead of a fork.

To sync the folly submodule the first time, you'll need
to issue:

git submodule init
git submodule update

From then on, you'll also want to make sure folly is up to
date by issuing `git submodule update` after a `git pull`.

Author: sgolemon

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "hphp/submodules/folly"]
+	path = hphp/submodules/folly
+	url = git://github.com/facebook/folly.git

CMake/FollySetup.cmake

@@ -0,0 +1,31 @@
+# folly-config.h is a generated file from autotools
+# We need to do the equivalent checks here and use
+# add_definitions as needed
+add_definitions(-DFOLLY_NO_CONFIG=1)
+
+INCLUDE(CheckCXXSourceCompiles)
+CHECK_CXX_SOURCE_COMPILES("
+extern \"C\" void (*test_ifunc(void))() { return 0; }
+void func() __attribute__((ifunc(\"test_ifunc\")));
+" FOLLY_IFUNC)
+if (FOLLY_IFUNC)
+        add_definitions("-DHAVE_IFUNC=1")
+endif()
+
+set(CMAKE_REQUIRED_LIBRARIES rt)
+CHECK_CXX_SOURCE_COMPILES("#include <time.h>
+int main() {
+  clock_gettime((clockid_t)0, NULL);
+  return 0;
+}" HAVE_CLOCK_GETTIME)
+
+if (HAVE_CLOCK_GETTIME)
+	add_definitions("-DFOLLY_HAVE_CLOCK_GETTIME=1")
+endif()
+set(CMAKE_REQUIRED_LIBRARIES)
+
+find_path(FEATURES_H_INCLUDE_DIR NAMES features.h)
+if (FEATURES_H_INCLUDE_DIR)
+	include_directories("${FEATURES_H_INCLUDE_DIR}")
+	add_definitions("-DFOLLY_HAVE_FEATURES_H=1")
+endif()

hphp/CMakeLists.txt

@@ -16,6 +16,7 @@
 #
 
 include(HPHPSetup)
+include(FollySetup)
 
 # HHVM Build
 SET(USE_HHVM TRUE)

hphp/submodules/folly

@@ -1,10 +1,9 @@
-# folly-config.h is a generated file from autotools
-# We need to do the equivalent checks here and use
-# add_definitions as needed
-add_definitions(-DFOLLY_NO_CONFIG=1)
-
 set(FOLLY_DIR "${CMAKE_CURRENT_SOURCE_DIR}/folly")
 
+if (NOT EXISTS "${FOLLY_DIR}/Portability.h")
+	message(FATAL_ERROR "${FOLLY_DIR}/Portability.h missing, did you forget to run `git submodule init && git submodule update`?")
+endif()
+
 # Generated files from folly/build/generate_*.py
 auto_sources(genfiles "*.cpp" "RECURSE" "${CMAKE_CURRENT_SOURCE_DIR}/gen")
 
@@ -20,11 +19,15 @@ foreach (file ${files})
 endforeach()
 list(REMOVE_ITEM files
 	${FOLLY_DIR}/Benchmark.cpp
+	${FOLLY_DIR}/build/GenerateFingerprintTables.cpp
+	${FOLLY_DIR}/detail/Clock.cpp
 	${FOLLY_DIR}/experimental/File.cpp
 	${FOLLY_DIR}/experimental/exception_tracer/ExceptionTracer.cpp
+	${FOLLY_DIR}/experimental/exception_tracer/ExceptionTracerBenchmark.cpp
 	${FOLLY_DIR}/experimental/exception_tracer/ExceptionTracerLib.cpp
 	${FOLLY_DIR}/experimental/exception_tracer/ExceptionTracerTest.cpp
 	${FOLLY_DIR}/experimental/io/AsyncIO.cpp
+	${FOLLY_DIR}/experimental/io/HugePageUtil.cpp
 	${FOLLY_DIR}/experimental/symbolizer/SymbolizerTest.cpp
 	${FOLLY_DIR}/experimental/symbolizer/ElfUtil.cpp
     )
@@ -40,6 +43,11 @@ endif()
 # and some other folly pieces we're not including yet
 # For now, that's not actually a requirement, so skip it
 list(REMOVE_ITEM files ${FOLLY_DIR}/Subprocess.cpp)
+
+# io/Compression requires snappy library
+# Don't add dep until we need it
+list(REMOVE_ITEM files ${FOLLY_DIR}/io/Compression.cpp)
+
 add_library(folly STATIC ${files} ${genfiles} ${cfiles} )
 
 find_package(Boost 1.48.0 COMPONENTS system program_options filesystem regex REQUIRED)
@@ -52,15 +60,6 @@ include_directories(${LIBGLOG_INCLUDE_DIR})
 find_package(PThread REQUIRED)
 include_directories(${LIBPTHREAD_INCLUDE_DIRS})
 
-INCLUDE(CheckCXXSourceCompiles)
-CHECK_CXX_SOURCE_COMPILES("
-extern \"C\" void (*test_ifunc(void))() { return 0; }
-void func() __attribute__((ifunc(\"test_ifunc\")));
-" FOLLY_IFUNC)
-if (FOLLY_IFUNC)
-	add_definitions("-DHAVE_IFUNC=1")
-endif()
-
 target_link_libraries(folly ${Boost_LIBRARIES}
                             ${LIBGLOG_LIBRARY}
                             ${LIBPTHREAD_LIBRARIES})

hphp/third_party/folly/CMakeLists.txt

@@ -0,0 +1 @@
+../../submodules/folly/folly