diff --git a/.gitignore b/.gitignore
index aa26514c9..872120bfb 100644
--- a/.gitignore
+++ b/.gitignore
@@ -19,6 +19,7 @@ Build
 # build files generated by autotools
 Makefile
 Makefile.in
+Makefilee
 config.log
 configure
 aclocal.m4
@@ -31,3 +32,9 @@ libtool
 .dirstamp
 /dispatch/module.modulemap
 /private/module.modulemap
+
+*.cmake
+CMakeCache.txt
+CMakeFiles
+*.so
+*.a
diff --git a/INSTALL.md b/INSTALL.md
index a426bcf30..23032d568 100644
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -168,3 +168,16 @@ to get the gold linker.
     ninja install
     ```
 
+### Building for Android
+
+To build the Swift Android toolchain including libdispatch, run:
+
+```
+swift/utils/android$ ./build-toolchain
+```
+
+Which will call at the end:
+
+```
+swift-corelibs-libdispatch$ ./build-android
+```
diff --git a/build-android b/build-android
new file mode 100755
index 000000000..818cdd137
--- /dev/null
+++ b/build-android
@@ -0,0 +1,44 @@
+#!/usr/bin/env bash
+#
+# build-android
+#
+# This source file is part of the Swift.org open source project
+#
+# Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+# Licensed under Apache License v2.0 with Runtime Library Exception
+#
+# See https://swift.org/LICENSE.txt for license information
+# See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+
+set -e
+
+cd "$(dirname $0)/.." || exit 1
+SWIFT_PATH=$PWD
+
+ANDROID_NDK_PATH="${ANDROID_NDK_PATH:?Please set the Android NDK path in the ANDROID_NDK_PATH environment variable}"
+SWIFT_ANDROID_BUILD_PATH="${SWIFT_PATH}/build/Ninja-ReleaseAssert"
+SWIFT_ANDROID_TOOLCHAIN_PATH="${SWIFT_PATH}/swift-android-toolchain"
+
+cd ${SWIFT_PATH}/swift-corelibs-libdispatch 
+sh autogen.sh
+env \
+    CC="$SWIFT_ANDROID_BUILD_PATH/llvm-linux-x86_64/bin/clang" \
+    CXX="$SWIFT_ANDROID_BUILD_PATH/llvm-linux-x86_64/bin/clang++" \
+    SWIFTC="$SWIFT_ANDROID_BUILD_PATH/swift-linux-x86_64/bin/swiftc" \
+    CFLAGS="-I$ANDROID_NDK_PATH/sysroot/usr/include" \
+    CPPFLAGS="-I$ANDROID_NDK_PATH/sysroot/usr/include -DTARGET_OS_EMBEDDED" \
+    ./configure \
+        --with-swift-toolchain="$SWIFT_ANDROID_TOOLCHAIN_PATH/usr" \
+        --with-build-variant=release \
+        --enable-android \
+        --host=arm-linux-androideabi \
+        --with-android-ndk=$ANDROID_NDK_PATH \
+        --with-android-api-level=21 \
+        --disable-build-tests \
+        --prefix=$SWIFT_ANDROID_TOOLCHAIN_PATH/usr
+
+make
+
+cp ${SWIFT_PATH}/swift-corelibs-libdispatch/src/.libs/libdispatch.so $SWIFT_ANDROID_TOOLCHAIN_PATH/usr/lib/swift/android/armv7
+cp ${SWIFT_PATH}/swift-corelibs-libdispatch/src/swift/Dispatch.{swiftmodule,swiftdoc} $SWIFT_ANDROID_TOOLCHAIN_PATH/usr/lib/swift/android/armv7
+
diff --git a/build-android-cmake b/build-android-cmake
new file mode 100755
index 000000000..db7fafee0
--- /dev/null
+++ b/build-android-cmake
@@ -0,0 +1,41 @@
+#!/usr/bin/env bash
+#
+# build-android
+#
+# This source file is part of the Swift.org open source project
+#
+# Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+# Licensed under Apache License v2.0 with Runtime Library Exception
+#
+# See https://swift.org/LICENSE.txt for license information
+# See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+
+set -e
+
+cd "$(dirname $0)/.." || exit 1
+SWIFT_PATH=$PWD
+
+ANDROID_NDK_PATH="${ANDROID_NDK_PATH:?Please set the Android NDK path in the ANDROID_NDK_PATH environment variable}"
+SWIFT_ANDROID_BUILD_PATH="${SWIFT_PATH}/build/Ninja-ReleaseAssert"
+SWIFT_ANDROID_TOOLCHAIN_PATH="${SWIFT_PATH}/swift-android-toolchain"
+
+cd ${SWIFT_PATH}/swift-corelibs-libdispatch 
+
+cmake \
+    -DBUILD_SHARED_LIBS=OFF \
+    -DENABLE_TESTING=OFF \
+    -DCMAKE_BUILD_TYPE=Release \
+    -DCMAKE_SYSTEM_NAME=Android \
+    -DCMAKE_SYSTEM_VERSION=21 \
+    -DCMAKE_ANDROID_ARCH_ABI=armeabi-v7a \
+    -DCMAKE_ANDROID_NDK=$ANDROID_NDK_PATH \
+    -DCMAKE_ANDROID_NDK_TOOLCHAIN_VERSION=$SWIFT_ANDROID_BUILD_PATH/llvm-linux-x86_64/bin/clang \
+    -DCMAKE_CXX_COMPILER=$SWIFT_ANDROID_BUILD_PATH/llvm-linux-x86_64/bin/clang++ \
+    -DCMAKE_SWIFT_COMPILER=$SWIFT_ANDROID_BUILD_PATH/swift-linux-x86_64/bin/swiftc \
+    -DENABLE_SWIFT=YES
+
+make
+
+cp ${SWIFT_PATH}/swift-corelibs-libdispatch/src/.libs/libdispatch.so $SWIFT_ANDROID_TOOLCHAIN_PATH/usr/lib/swift/android/armv7
+cp ${SWIFT_PATH}/swift-corelibs-libdispatch/src/swift/Dispatch.{swiftmodule,swiftdoc} $SWIFT_ANDROID_TOOLCHAIN_PATH/usr/lib/swift/android/armv7
+
diff --git a/os/linux_base.h b/os/linux_base.h
index 58b497148..278d37360 100644
--- a/os/linux_base.h
+++ b/os/linux_base.h
@@ -13,9 +13,11 @@
 #ifndef __OS_LINUX_BASE__
 #define __OS_LINUX_BASE__
 
+#ifndef __ANDROID__
 #if __has_include(<sys/sysmacros.h>)
 #include <sys/sysmacros.h>
 #endif
+#endif
 #include <sys/param.h>
 
 #if __has_include(<sys/cdefs.h>)
diff --git a/src/shims/hw_config.h b/src/shims/hw_config.h
index 485dad663..1d164048e 100644
--- a/src/shims/hw_config.h
+++ b/src/shims/hw_config.h
@@ -104,7 +104,7 @@ _dispatch_hw_get_config(_dispatch_hw_config_t c)
 		return (uint32_t)sysconf(_SC_NPROCESSORS_CONF);
 	case _dispatch_hw_config_active_cpus:
 		{
-#ifdef __USE_GNU
+#if defined(__USE_GNU) && !defined(__ANDROID__)
 			// Prefer pthread_getaffinity_np because it considers
 			// scheduler cpu affinity.  This matters if the program
 			// is restricted to a subset of the online cpus (eg via numactl).