5_1-new: Fix building with clang/clang++ (#1866)

* Have clang and libc++ working.

If any clang users run into problems, remember to have libc++ and libc++abi set up.
Fixes
stepmania/src/arch/ArchHooks/ArchHooks.h:37:27: error:
      variable has incomplete type 'tm'
        virtual void SetTime( tm ) { }
                                 ^
/usr/include/wchar.h:83:8: note: forward declaration of 'tm'
struct tm;
       ^

* Add noexcept to swap.

See https://github.com/stepmania/stepmania/commit/e860773799f01d02f281c8c39421e7e34658788d#commitcomment-32674320

* Use standard c++11 for handling unexpected exceptions

The cxxabi.h header can make linking difficult.

.travis.yml

@@ -32,6 +32,8 @@ matrix:
                         - libxtst-dev
                         - libxrandr-dev
                         - libglew-dev
+                        - libc++-dev
+                        - libstdc++-4.8-dev
 
         -
             env: CXX_COMPILER=clang++-3.6 CC_COMPILER=clang-3.6 BUILD_TYPE=Release WITH_FFMPEG=ON WITH_FFMPEG_JOBS=1

src/CMakeLists.txt

@@ -386,6 +386,7 @@ else() # Linux
     sm_add_compile_flag("${SM_EXE_NAME}" "-stdlib=libc++")
     set_target_properties("${SM_EXE_NAME}"
                           PROPERTIES LINK_FLAGS "-stdlib=libc++")
+    sm_add_compile_flag("jsoncpp" "-stdlib=libc++")
   endif()
 endif()
 

src/NoteData.h

@@ -382,7 +382,13 @@ public:
 /** @brief Allow a quick way to swap notedata. */
 namespace std
 {
-	template<> inline void swap<NoteData>( NoteData &nd1, NoteData &nd2 ){ nd1.swap( nd2 ); }
+	template<> inline void swap<NoteData>( NoteData &nd1, NoteData &nd2 )
+#if !defined(_MSC_VER)
+	noexcept(is_nothrow_move_constructible<NoteData>::value && is_nothrow_move_assignable<NoteData>::value)
+#endif
+	{
+		nd1.swap( nd2 );
+	}
 }
 
 #endif

src/arch/ArchHooks/ArchHooks.h

@@ -1,6 +1,8 @@
 #ifndef ARCH_HOOKS_H
 #define ARCH_HOOKS_H
 
+#include <ctime>
+
 struct lua_State;
 class ArchHooks
 {

src/archutils/Unix/AssertionHandler.cpp

@@ -46,18 +46,28 @@ extern "C" void __assert_perror_fail( int errnum, const char *file, unsigned int
 
 /* Catch unhandled C++ exceptions.  Note that this works in g++ even with -fno-exceptions, in
  * which case it'll be called if any exceptions are thrown at all. */
-#include <cxxabi.h>
 void UnexpectedExceptionHandler()
 {
-	type_info *pException = abi::__cxa_current_exception_type();
+	std::exception_ptr exptr = std::current_exception();
-	char const *pName = pException->name();
+	try
-	int iStatus = -1;
+	{
-	char *pDem = abi::__cxa_demangle( pName, 0, 0, &iStatus );
+		std::rethrow_exception(exptr);
-
+	}
-	const RString error = ssprintf("Unhandled exception: %s", iStatus? pName:pDem);
+	catch (std::exception &ex)
+	{
 #if defined(CRASH_HANDLER)
+		const RString error = ssprintf("Unhandled exception: %s", ex.what());
 		sm_crash( error );
 #endif
+	}
+	// TODO: Don't throw anything not subclassing std::exception
+	catch(...)
+	{
+#if defined(CRASH_HANDLER)
+		const RString error = ssprintf("Unknown exception.");
+		sm_crash( error );
+#endif
+	}
 }
 
 void InstallExceptionHandler()