Export more symbols on React Native

Reviewed By: skotchvail

Differential Revision: D5157649

fbshipit-source-id: 8d04dff3a8564d3a095591aa982c9b72ace9a8b7

ReactCommon/jschelpers/JSCHelpers.h

@@ -9,6 +9,10 @@
 #include <jschelpers/JavaScriptCore.h>
 #include <jschelpers/Value.h>
 
+#ifndef RN_EXPORT
+#define RN_EXPORT __attribute__((visibility("default")))
+#endif
+
 namespace facebook {
 namespace react {
 
@@ -47,7 +51,7 @@ JSObjectRef makeFunction(
     const char* name,
     JSFunction function);
 
-void installGlobalFunction(
+RN_EXPORT void installGlobalFunction(
     JSGlobalContextRef ctx,
     const char* name,
     JSFunction function);

ReactCommon/jschelpers/Value.h

@@ -307,15 +307,15 @@ public:
     return getType() == kJSTypeObject;
   }
 
-  Object asObject() const;
+  RN_EXPORT Object asObject() const;
 
   bool isString() const {
     return getType() == kJSTypeString;
   }
 
-  String toString() const;
+  RN_EXPORT String toString() const;
 
-  static Value makeError(JSContextRef ctx, const char *error);
+  RN_EXPORT static Value makeError(JSContextRef ctx, const char *error);
 
   static Value makeNumber(JSContextRef ctx, double value) {
     return Value(ctx, JSC_JSValueMakeNumber(ctx, value));