Don't hardcode build-tools version

android/README.ANDROID

@@ -48,9 +48,8 @@ Android NDK r12b.
 
 You need to create proper "android-sdk" and "android-ndk" symlinks in the
 directory with Android project, so that the compilation script will have access
-to the SDK and NDK.
-
-These paths can be also set in SDK_PATH and NDK_PATH environmental variables.
+to the SDK and NDK. These paths can be also set in SDK_PATH and NDK_PATH 
+environmental variables.
 
 Before running the compilation, run the generate_assets script, so that
 selected assets will be copied to "assets" directory, and then included in the
@@ -78,9 +77,10 @@ you have to manually sign the apk with your key and run zipalign.
 Additionally you can choose the build tool by setting BUILD_TOOL environment
 variable to "gradle" or "ant". Note that ant has been already removed from
 Android SDK, so you have to use SDK <= 25.2.5 for building with ant. By default 
-the BUILD_TOOL is set to "gradle". It has hardcoded version of SDK build-tools 
-that are set to "25.0.3", so you have to use this particular version (or you can
-edit build.gradle file).
+the BUILD_TOOL is set to "gradle".
+
+You can override the SDK build-tools version by setting the BUILD_TOOLS_VER
+environment variable.
 
 Basically if all dependencies are installed in the system, it should be enough
 to just run:

android/build.gradle

@@ -15,8 +15,8 @@ apply plugin: 'com.android.application'
 
 android
 {
-    compileSdkVersion sdkVersion.toInteger()
-    buildToolsVersion "25.0.3"
+    compileSdkVersion sdk_version.toInteger()
+    buildToolsVersion build_tools_ver
 
     sourceSets
     {

android/make.sh

@@ -155,6 +155,24 @@ if [ ! -d "$SDK_PATH" ]; then
     exit
 fi
 
+# Find newest build-tools version
+if [ -z "$BUILD_TOOLS_VER" ]; then
+    BUILD_TOOLS_DIRS=`ls -1 "$SDK_PATH/build-tools" | sort -V -r`
+   
+    for DIR in $BUILD_TOOLS_DIRS; do
+        if [ "$DIR" = `echo $DIR | sed 's/[^0-9,.]//g'` ]; then
+            BUILD_TOOLS_VER="$DIR"
+            break
+        fi
+    done
+fi
+
+if [ -z "$BUILD_TOOLS_VER" ] || [ ! -d "$SDK_PATH/build-tools/$BUILD_TOOLS_VER" ]; then
+    echo "Error: Couldn't detect build-tools version."
+    exit
+fi
+
+
 # Standalone toolchain
 if [ ! -f "$DIRNAME/obj/make_standalone_toolchain.stamp" ]; then
     echo "Creating standalone toolchain"
@@ -326,9 +344,13 @@ echo "Building APK"
 
 if [ "$BUILD_TOOL" = "gradle" ]; then
     export ANDROID_HOME="$SDK_PATH"
-    gradle -PsdkVersion=$SDK_VERSION $GRADLE_BUILD_TYPE
+    gradle -Psdk_version=$SDK_VERSION           \
+           -Pbuild_tools_ver="$BUILD_TOOLS_VER" \
+           $GRADLE_BUILD_TYPE
 elif [ "$BUILD_TOOL" = "ant" ]; then
-    ant $ANT_BUILD_TYPE -Dsdk.dir="$SDK_PATH" -Dtarget=$NDK_PLATFORM
+    ant -Dsdk.dir="$SDK_PATH"  \
+        -Dtarget=$NDK_PLATFORM \
+        $ANT_BUILD_TYPE
 fi
 
 check_error