fix CBManager crash on macOS <10.15

Cargo.toml

@@ -49,6 +49,7 @@ jni-utils = "0.1.1"
 cocoa = "0.25.0"
 objc = "0.2.7"
 libc = "0.2.147"
+os_info = "3.7.0"
 
 [target.'cfg(target_os = "windows")'.dependencies]
 windows = { version = "0.51.1", features = ["Devices_Bluetooth", "Devices_Bluetooth_GenericAttributeProfile", "Devices_Bluetooth_Advertisement", "Devices_Radios", "Foundation_Collections", "Foundation", "Storage_Streams"] }

src/corebluetooth/framework.rs

@@ -174,7 +174,13 @@ pub mod cb {
 
     // CBManager
     pub fn manager_authorization() -> CBManagerAuthorization {
-        unsafe { msg_send![class!(CBManager), authorization] }
+        use os_info::Version::Semantic as OSSemVer;
+
+        if os_info::get().version() >= &OSSemVer(10, 15, 0) {
+            unsafe { msg_send![class!(CBManager), authorization] }
+        } else {
+            CBManagerAuthorization::NotDetermined
+        }
     }
 
     #[derive(Copy, Clone, Debug, Eq, PartialEq)]