Upgrade rcutils to C++17. (ros2#392)

* Upgrade rcutils to C++17.

This upgrade was more involved than just increasing the
CMAKE_CXX_STANDARD version.  In C++17, apparently 'noexcept'
became part of the type system.  This is problematic because
some functions that we use from the underlying libc, like
'stat', actually specify nothrow in their function declaration.
This causes the type system to reject our mock shims, since
the types are no longer totally compatible.

To work around this, introduce a 'remove_noexcept' type into
the system which effectively removes the 'noexcept' specifier
for any function that it uses.  With that in place, everything
here works with C++17.  See the comments in remove_noexcept.hpp
for details on the provenance of that code.

Signed-off-by: Chris Lalancette <clalancette@openrobotics.org>

Author: clalancette

CMakeLists.txt

@@ -6,9 +6,9 @@ project(rcutils)
 if(NOT CMAKE_C_STANDARD)
   set(CMAKE_C_STANDARD 11)
 endif()
-# Default to C++14
+# Default to C++17
 if(NOT CMAKE_CXX_STANDARD)
-  set(CMAKE_CXX_STANDARD 14)
+  set(CMAKE_CXX_STANDARD 17)
 endif()
 
 include(CheckLibraryExists)
@@ -143,16 +143,18 @@ install(TARGETS ${PROJECT_NAME} EXPORT ${PROJECT_NAME}
   RUNTIME DESTINATION bin)
 
 if(BUILD_TESTING)
-  if(NOT WIN32)
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++14")
-  endif()
-
   find_package(performance_test_fixture REQUIRED)
 
   find_package(ament_cmake_gmock REQUIRED)
   find_package(ament_cmake_gtest REQUIRED)
   find_package(ament_cmake_pytest REQUIRED)
   find_package(ament_lint_auto REQUIRED)
+  # cppcheck 1.90 doesn't understand some of the syntax in remove_noexcept.hpp
+  # Since we already have cppcheck disabled on Linux, just disable it completely
+  # for this package.
+  list(APPEND AMENT_LINT_AUTO_EXCLUDE
+    ament_cmake_cppcheck
+  )
   ament_lint_auto_find_test_dependencies()
 
   find_package(launch_testing_ament_cmake REQUIRED)

test/mocking_utils/filesystem.hpp

@@ -33,6 +33,7 @@
 #endif
 #endif
 
+#include <functional>
 #include <map>
 #include <string>
 #include <type_traits>

test/mocking_utils/patch.hpp

@@ -35,6 +35,8 @@
 #include "mimick/mimick.h"
 #include "rcutils/macros.h"
 
+#include "remove_noexcept.hpp"
+
 namespace mocking_utils
 {
 
@@ -215,7 +217,9 @@ class Patch<ID, ReturnT(ArgTs...)>
    *   trampoline, as setup by the dynamic linker.
    * \return a mocking_utils::Patch instance.
    */
-  explicit Patch(const std::string & target, std::function<ReturnT(ArgTs...)> proxy)
+  explicit Patch(
+    const std::string & target,
+    std::function<remove_noexcept_t<ReturnT(ArgTs...)>> proxy)
   : proxy_(proxy)
   {
     auto MMK_MANGLE(mock_type, create) =
@@ -291,9 +295,9 @@ class Patch<ID, ReturnT(ArgTs...)>
  * \sa mocking_utils::Patch for further reference.
  */
 template<size_t ID, typename SignatureT>
-auto make_patch(const std::string & target, std::function<SignatureT> proxy)
+auto make_patch(const std::string & target, std::function<remove_noexcept_t<SignatureT>> proxy)
 {
-  return Patch<ID, SignatureT>(target, proxy);
+  return Patch<ID, remove_noexcept_t<SignatureT>>(target, proxy);
 }
 
 /// Define a dummy operator `op` for a given `type`.