turn on RTTI for v8pp library

and turn it off only for v8pp/context.cpp on macOS, because exceptions there
can't be catched if they were thrown from dylib with disabled RTTI
More details in Stackoverflow quiestion ["Problems throwing and catching exceptions on OS X with -fno-rtti"](https://stackoverflow.com/questions/21737201/problems-throwing-and-catching-exceptions-on-os-x-with-fno-rtti)

See issue #176

Author: pmed

v8pp/CMakeLists.txt

@@ -60,7 +60,7 @@ if(MSVC)
 	# set warning level 3 for system headers
 	list(APPEND V8PP_COMPILE_OPTIONS /experimental:external /external:anglebrackets /external:W3)
 else()
-	set(V8PP_COMPILE_OPTIONS -fno-rtti -fexceptions -Wall -Wextra -Wpedantic)
+	set(V8PP_COMPILE_OPTIONS -frtti -fexceptions -Wall -Wextra -Wpedantic)
 endif()
 
 if(V8PP_HEADER_ONLY)
@@ -84,6 +84,11 @@ else()
 	if(BUILD_SHARED_LIBS)
 		target_link_libraries(v8pp PUBLIC ${CMAKE_DL_LIBS})
 	endif()
+	if(APPLE)
+		# turn off RTTI to avoid generating typeinfo for v8::ArrayBuffer::Allocator
+		# used in context.cpp
+		set_source_files_properties(context.cpp PROPERTIES COMPILE_FLAGS -fno-rtti)
+	endif()
 endif()
 
 #source_group(TREE ${CMAKE_CURRENT_SOURCE_DIR} FILES ${V8PP_HEADERS} ${V8PP_SOURCES})