Accept NDK r9

Change-Id: Ie7368d0995653d7051b3c67d4b7667e68787da8a

configure.ac

@@ -161,10 +161,10 @@ if test -n "$with_android_ndk"; then
     ANDROID_NDK_VERSION=`cut -f1 -d' ' <$ANDROID_NDK_HOME/RELEASE.TXT`
 
     case $ANDROID_NDK_VERSION in
-    r8*)
+    r8*|r9)
         ;;
     *)
-        AC_MSG_ERROR([Unsupported NDK version $ANDROID_NDK_VERSION, only r8* versions are supported])
+        AC_MSG_ERROR([Unsupported NDK version $ANDROID_NDK_VERSION, only r8* and r9 versions are supported])
         ;;
     esac
 
@@ -201,12 +201,12 @@ if test -n "$with_android_ndk"; then
     fi
 
     # Check if there is a 64-bit tool-chain. Google provides a NDK with 64-bit tool-chain binaries in
-    # NDK r8e, and for earlier NDKs it was possible to build one yourself. Using a 64-bit linker is
-    # required if you compile large parts of the code with -g. A 32-bit linker just won't manage to
-    # link the (app-specific) single huge .so that is built for the apps in android/experimental/* if
-    # there is debug information in a significant part of the object files. (A 64-bit ld.gold grows to
-    # much over 10 gigabytes of virtual space when linking such a .so if all objects have been built
-    # with debug information.)
+    # NDK r8e and later, and for earlier NDKs it was possible to build one yourself. Using a 64-bit
+    # linker is required if you compile large parts of the code with -g. A 32-bit linker just won't
+    # manage to link the (app-specific) single huge .so that is built for the apps in
+    # android/experimental/* if there is debug information in a significant part of the object files.
+    # (A 64-bit ld.gold grows to much over 10 gigabytes of virtual space when linking such a .so if
+    # all objects have been built with debug information.)
     toolchain_system='*'
     if test $build_os = linux-gnu; then
         ANDROID_COMPILER_BIN=$ANDROID_COMPILER_DIR/prebuilt/linux-x86/bin