Check for ANDROID_NDK definition in android-aar.sh

Otherwise, the script can report success even though nothing compiles.

dist-build/android-aar.sh

@@ -5,6 +5,13 @@
 # To simplify linking, library variants have distinct names: sodium, sodium-static, sodium-minimal and sodium-minimal-static.
 
 SODIUM_VERSION="1.0.20.0"
+
+if [ -z "$ANDROID_NDK_HOME" ]; then
+  echo "You should probably set ANDROID_NDK_HOME to the directory containing"
+  echo "the Android NDK."
+  exit 1
+fi
+
 NDK_VERSION=$(grep "Pkg.Revision = " <"${ANDROID_NDK_HOME}/source.properties" | cut -f 2 -d '=' | cut -f 2 -d' ' | cut -f 1 -d'.')
 DEST_PATH=$(mktemp -d)
 

dist-build/android-build.sh

@@ -11,7 +11,7 @@ export NDK_API_VERSION_COMPAT="$(echo "$NDK_PLATFORM_COMPAT" | sed 's/^android-/
 
 if [ -z "$ANDROID_NDK_HOME" ]; then
   echo "You should probably set ANDROID_NDK_HOME to the directory containing"
-  echo "the Android NDK"
+  echo "the Android NDK."
   exit 1
 fi