Merge pull request #2472 from Roomle/fix/CppEmscripten

fix cpp cmake for emscripten

Author: parrt

contributors.txt

@@ -214,6 +214,7 @@ YYYY/MM/DD, github id, Full name, email
 2018/11/29, hannemann-tamas, Ralf Hannemann-Tamas, [email protected]
 2018/12/20, WalterCouto, Walter Couto, [email protected]
 2018/12/23, youkaichao, Kaichao You, [email protected]
+2019/01/16, kuegi, Markus Zancolo, [email protected]
 2019/02/06, ralucado, Cristina Raluca Vijulie, ralucris.v[at]gmail[dot]com
 2019/02/23, gedimitr, Gerasimos Dimitriadis, [email protected]
 2019/03/13, base698, Justin Thomas, [email protected]

runtime/Cpp/CMakeLists.txt

@@ -122,7 +122,9 @@ elseif ("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang" AND ( CMAKE_SYSTEM_NAME MATCH
     endif()
 elseif(MSVC_VERSION GREATER 1800 OR MSVC_VERSION EQUAL 1800)
   # Visual Studio 2012+ supports c++11 features 
-else ()
+elseif(CMAKE_SYSTEM_NAME MATCHES "Emscripten")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -stdlib=libc++")
+else()
     message(FATAL_ERROR "Your C++ compiler does not support C++11.")
 endif()