Source release 16.4.0

third_party/protobuf/cmake/CMakeLists.txt

@@ -28,6 +28,14 @@ else()
   set(CMAKE_CXX_EXTENSIONS OFF)
 endif()
 
+# The Intel compiler isn't able to deal with noinline member functions of
+# template classses defined in headers.  As such it spams the output with
+#   warning #2196: routine is both "inline" and "noinline"
+# This silences that warning.
+if (CMAKE_CXX_COMPILER_ID MATCHES Intel)
+  string(APPEND CMAKE_CXX_FLAGS " -diag-disable=2196")
+endif()
+
 # Options
 option(protobuf_BUILD_TESTS "Build tests" ON)
 option(protobuf_BUILD_CONFORMANCE "Build conformance tests" OFF)
@@ -132,6 +140,25 @@ if (HAVE_ZLIB)
   add_definitions(-DHAVE_ZLIB)
 endif (HAVE_ZLIB)
 
+# We need to link with libatomic on systems that do not have builtin atomics, or
+# don't have builtin support for 8 byte atomics
+set(protobuf_LINK_LIBATOMIC false)
+if (NOT MSVC)
+  include(CheckCXXSourceCompiles)
+  set(OLD_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
+  set(CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS} -std=c++11)
+  check_cxx_source_compiles("
+    #include <atomic>
+    int main() {
+      return std::atomic<int64_t>{};
+    }
+  " protobuf_HAVE_BUILTIN_ATOMICS)
+  if (NOT protobuf_HAVE_BUILTIN_ATOMICS)
+    set(protobuf_LINK_LIBATOMIC true)
+  endif (NOT protobuf_HAVE_BUILTIN_ATOMICS)
+  set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS})
+endif (NOT MSVC)
+
 if (protobuf_BUILD_SHARED_LIBS)
   set(protobuf_SHARED_OR_STATIC "SHARED")
 else (protobuf_BUILD_SHARED_LIBS)
@@ -180,7 +207,7 @@ if (MSVC)
   configure_file(extract_includes.bat.in extract_includes.bat)
 
   # Suppress linker warnings about files with no symbols defined.
-  set(CMAKE_STATIC_LINKER_FLAGS /ignore:4221)
+  set(CMAKE_STATIC_LINKER_FLAGS "${CMAKE_STATIC_LINKER_FLAGS} /ignore:4221")
 
   # Configure Resource Compiler
   enable_language(RC)