[ReactNative] Remove module info from the data section + allow extern…

…al modules

Summary:
@public

The information we required about the exported methods were previously stored
on the binary's DATA section, which didn't allow to access methods on different
static libraries, or in any dynamic library at all. Instead of fetching information
from all the DATA segments, this diff changes the macro in order to create a
new method, that returns the required information about the original method. The
module itself is registered at load time, and on the bridge initialization all
the auto-generated methods are called to gather the methods' information.

Test Plan:
UIExplorer previously had a dependency on `RCTTest`, because it had a `TestModule`
that had to be on the same library. `RCTTest` is now a dependency of
`UIExplorerIntegrationTests`. So the tests themselves running should test it.

Examples/UIExplorer/UIExplorer.xcodeproj/project.pbxproj

@@ -30,6 +30,7 @@
 		1497CFB21B21F5E400C1F8F2 /* RCTSparseArrayTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 1497CFAA1B21F5E400C1F8F2 /* RCTSparseArrayTests.m */; };
 		1497CFB31B21F5E400C1F8F2 /* RCTUIManagerTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 1497CFAB1B21F5E400C1F8F2 /* RCTUIManagerTests.m */; };
 		14AADF051AC3DBB1002390C9 /* libReact.a in Frameworks */ = {isa = PBXBuildFile; fileRef = 14AADF041AC3DB95002390C9 /* libReact.a */; };
+		14B6DA821B276C5900BF4DD1 /* libRCTTest.a in Frameworks */ = {isa = PBXBuildFile; fileRef = 58005BEE1ABA80530062E044 /* libRCTTest.a */; };
 		14D6D7111B220EB3001FB087 /* libOCMock.a in Frameworks */ = {isa = PBXBuildFile; fileRef = 14D6D7101B220EB3001FB087 /* libOCMock.a */; };
 		14D6D71E1B2222EF001FB087 /* libRCTActionSheet.a in Frameworks */ = {isa = PBXBuildFile; fileRef = 147CED4B1AB34F8C00DA3E4C /* libRCTActionSheet.a */; };
 		14D6D71F1B2222EF001FB087 /* libRCTAdSupport.a in Frameworks */ = {isa = PBXBuildFile; fileRef = 1344545A1AAFCAAE003F0779 /* libRCTAdSupport.a */; };
@@ -44,7 +45,6 @@
 		14D6D7281B2222EF001FB087 /* libRCTWebSocket.a in Frameworks */ = {isa = PBXBuildFile; fileRef = 139FDED91B0651EA00C62182 /* libRCTWebSocket.a */; };
 		14D6D7291B2222EF001FB087 /* libReact.a in Frameworks */ = {isa = PBXBuildFile; fileRef = 14AADF041AC3DB95002390C9 /* libReact.a */; };
 		14DC67F41AB71881001358AB /* libRCTPushNotification.a in Frameworks */ = {isa = PBXBuildFile; fileRef = 14DC67F11AB71876001358AB /* libRCTPushNotification.a */; };
-		58005BF21ABA80A60062E044 /* libRCTTest.a in Frameworks */ = {isa = PBXBuildFile; fileRef = 58005BEE1ABA80530062E044 /* libRCTTest.a */; };
 		834C36EC1AF8DED70019C93C /* libRCTSettings.a in Frameworks */ = {isa = PBXBuildFile; fileRef = 834C36D21AF8DA610019C93C /* libRCTSettings.a */; };
 		D85B829E1AB6D5D7003F4FE2 /* libRCTVibration.a in Frameworks */ = {isa = PBXBuildFile; fileRef = D85B829C1AB6D5CE003F4FE2 /* libRCTVibration.a */; };
 /* End PBXBuildFile section */
@@ -229,7 +229,6 @@
 				1341802C1AA9178B003F314A /* libRCTNetwork.a in Frameworks */,
 				14DC67F41AB71881001358AB /* libRCTPushNotification.a in Frameworks */,
 				834C36EC1AF8DED70019C93C /* libRCTSettings.a in Frameworks */,
-				58005BF21ABA80A60062E044 /* libRCTTest.a in Frameworks */,
 				134180011AA9153C003F314A /* libRCTText.a in Frameworks */,
 				D85B829E1AB6D5D7003F4FE2 /* libRCTVibration.a in Frameworks */,
 				139FDEDB1B0651FB00C62182 /* libRCTWebSocket.a in Frameworks */,
@@ -240,6 +239,7 @@
 			isa = PBXFrameworksBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				14B6DA821B276C5900BF4DD1 /* libRCTTest.a in Frameworks */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -865,7 +865,7 @@
 					"$(SRCROOT)/../../React/**",
 				);
 				INFOPLIST_FILE = "$(SRCROOT)/UIExplorer/Info.plist";
-				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks";
+				LD_RUNPATH_SEARCH_PATHS = "$(inherited)";
 				LIBRARY_SEARCH_PATHS = "$(inherited)";
 				OTHER_LDFLAGS = "-ObjC";
 				PRODUCT_NAME = UIExplorer;
@@ -883,7 +883,7 @@
 					"$(SRCROOT)/../../React/**",
 				);
 				INFOPLIST_FILE = "$(SRCROOT)/UIExplorer/Info.plist";
-				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks";
+				LD_RUNPATH_SEARCH_PATHS = "$(inherited)";
 				LIBRARY_SEARCH_PATHS = "$(inherited)";
 				OTHER_LDFLAGS = "-ObjC";
 				PRODUCT_NAME = UIExplorer;
@@ -907,6 +907,12 @@
 				INFOPLIST_FILE = UIExplorerIntegrationTests/Info.plist;
 				IPHONEOS_DEPLOYMENT_TARGET = 8.3;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
+				OTHER_LDFLAGS = (
+					"$(inherited)",
+					"-framework",
+					XCTest,
+					"-ObjC",
+				);
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				TEST_HOST = "$(BUILT_PRODUCTS_DIR)/UIExplorer.app/UIExplorer";
 			};
@@ -926,6 +932,12 @@
 				INFOPLIST_FILE = UIExplorerIntegrationTests/Info.plist;
 				IPHONEOS_DEPLOYMENT_TARGET = 8.3;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
+				OTHER_LDFLAGS = (
+					"$(inherited)",
+					"-framework",
+					XCTest,
+					"-ObjC",
+				);
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				TEST_HOST = "$(BUILT_PRODUCTS_DIR)/UIExplorer.app/UIExplorer";
 			};

React/Base/RCTBridge.h

@@ -21,17 +21,17 @@
 /**
  * This notification triggers a reload of all bridges currently running.
  */
-extern NSString *const RCTReloadNotification;
+RCT_EXTERN NSString *const RCTReloadNotification;
 
 /**
  * This notification fires when the bridge has finished loading.
  */
-extern NSString *const RCTJavaScriptDidLoadNotification;
+RCT_EXTERN NSString *const RCTJavaScriptDidLoadNotification;
 
 /**
  * This notification fires when the bridge failed to load.
  */
-extern NSString *const RCTJavaScriptDidFailToLoadNotification;
+RCT_EXTERN NSString *const RCTJavaScriptDidFailToLoadNotification;
 
 /**
  * This block can be used to instantiate modules that require additional
@@ -43,6 +43,13 @@ extern NSString *const RCTJavaScriptDidFailToLoadNotification;
  */
 typedef NSArray *(^RCTBridgeModuleProviderBlock)(void);
 
+/**
+ * Register the given class as a bridge module. All modules must be registered
+ * prior to the first bridge initialization.
+ *
+ */
+RCT_EXTERN void RCTRegisterModule(Class);
+
 /**
  * This function returns the module name for a given class.
  */