Fix warnings

Author: liamappelbe

pkgs/ffigen/lib/src/code_generator/objc_block.dart

@@ -400,6 +400,7 @@ ref.pointer.ref.invoke.cast<${_helper.trampNatFnCType}>()
     final blockingListenerRetains = [_waiterParam.name, ...retains];
 
     final argStr = argsReceived.join(', ');
+    final declArgStr = argStr.isEmpty ? 'void' : argStr;
     final blockingArgStr = [
       _waiterParam.getNativeType(varName: _waiterParam.name),
       ...argsReceived,
@@ -416,7 +417,7 @@ ref.pointer.ref.invoke.cast<${_helper.trampNatFnCType}>()
 
     return '''
 
-typedef ${returnType.getNativeType()} (^$listenerName)($argStr);
+typedef ${returnType.getNativeType()} (^$listenerName)($declArgStr);
 __attribute__((visibility("default"))) __attribute__((used))
 $listenerName $listenerWrapper($listenerName block) NS_RETURNS_RETAINED {
   return ^void($argStr) {

pkgs/objective_c/src/objective_c.m

@@ -77,8 +77,8 @@ FFI_EXPORT Version DOBJC_getOsVesion(void) {
   NSOperatingSystemVersion objc_version =
       [[NSProcessInfo processInfo] operatingSystemVersion];
   Version c_version;
-  c_version.major = objc_version.majorVersion;
-  c_version.minor = objc_version.minorVersion;
-  c_version.patch = objc_version.patchVersion;
+  c_version.major = (int)objc_version.majorVersion;
+  c_version.minor = (int)objc_version.minorVersion;
+  c_version.patch = (int)objc_version.patchVersion;
   return c_version;
 }

pkgs/objective_c/src/objective_c_bindings_generated.m

@@ -127,7 +127,7 @@ BOOL  _ObjectiveCBindings_protocolTrampoline_w1e3k0(id target, void * sel, struc
   return ((_ProtocolTrampoline_8)((id (*)(id, SEL, SEL))objc_msgSend)(target, @selector(getDOBJCDartProtocolMethodForSelector:), sel))(sel, arg1);
 }
 
-typedef void  (^_ListenerTrampoline)();
+typedef void  (^_ListenerTrampoline)(void);
 __attribute__((visibility("default"))) __attribute__((used))
 _ListenerTrampoline _ObjectiveCBindings_wrapListenerBlock_1pl9qdv(_ListenerTrampoline block) NS_RETURNS_RETAINED {
   return ^void() {