android/AndroidManifest.xml: raise minSdkVersion to 24

NEWS

@@ -6,6 +6,8 @@ ver 0.23.14 (not yet released)
   - wasapi: fix problem setting volume
 * more libfmt 10 fixes
 * fix auto-detected systemd unit directory
+* Android
+  - require Android 7 or newer
 
 ver 0.23.13 (2023/05/22)
 * input

android/AndroidManifest.xml

@@ -5,7 +5,7 @@
           android:versionCode="72"
           android:versionName="0.23.14">
 
-  <uses-sdk android:minSdkVersion="21" android:targetSdkVersion="30"/>
+  <uses-sdk android:minSdkVersion="24" android:targetSdkVersion="30"/>
 
   <uses-feature android:name="android.software.leanback"
                 android:required="false" />

android/build.py

@@ -78,7 +78,7 @@ class AndroidNdkToolchain:
         self.build_path = build_path
 
         ndk_arch = abi_info['ndk_arch']
-        android_api_level = '21'
+        android_api_level = '24'
 
         install_prefix = os.path.join(arch_path, 'root')