Use termux' NDK
--- ./releng/setup-env.sh	2018-02-26 19:22:57.000000000 +0000
+++ ../setup-env.sh	2018-03-05 12:49:07.583020888 +0000
@@ -92,8 +92,8 @@
 fi
 
 if [ $host_platform = android ]; then
-  ndk_required_name=r15c
-  ndk_required_version=15.2.4203891
+  ndk_required_name=r17
+  ndk_required_version=17.0.4754217
   if [ -n "$ANDROID_NDK_ROOT" ]; then
     if [ -f "$ANDROID_NDK_ROOT/source.properties" ]; then
       ndk_installed_version=$(grep Pkg.Revision "$ANDROID_NDK_ROOT/source.properties" | awk '{ print $NF; }')
@@ -370,7 +370,7 @@
 
     case $host_arch in
       x86)
-        android_target_platform=14
+        android_target_platform=21
         android_host_abi=x86
         android_host_target=i686-none-linux-android
         android_host_toolchain=x86-4.9
@@ -388,7 +388,7 @@
         android_host_ldflags="-fuse-ld=gold"
         ;;
       arm)
-        android_target_platform=14
+        android_target_platform=21
         android_host_abi=armeabi-v7a
         android_host_target=armv7-none-linux-androideabi
         android_host_toolchain=arm-linux-androideabi-4.9
@@ -527,7 +527,6 @@
     if [ $android_have_unwind == yes ]; then
       meson_cpp_link_args="$meson_cpp_link_args, '$cxx_libdir/libunwind.a'"
     fi
-    meson_cpp_link_args="$meson_cpp_link_args, '$cxx_libdir/libandroid_support.a'"
     if [ $android_have_unwind == yes ]; then
       meson_cpp_link_args="$meson_cpp_link_args, '-Wl,--exclude-libs,$cxx_libdir/libunwind.a'"
     fi