Update common.h

src/common.h

@@ -33,6 +33,10 @@
 #define UNREACHABLE() throw std::runtime_error( __FILE__ + std::string(":") + std::to_string(__LINE__) + " UNREACHABLE()!");
 #endif
 
+#ifdef __EMSCRIPTEN__
+#include <emscripten.h>
+#endif
+
 #define PK_VERSION "0.8.0"
 
 typedef int64_t i64;