This adds an Android target for the stdlib. It is also the first
example of cross-compiling outside of Darwin.
Mailing list discussions:
1. https://lists.swift.org/pipermail/swift-dev/Week-of-Mon-20151207/000171.html
2. https://lists.swift.org/pipermail/swift-dev/Week-of-Mon-20151214/000492.html
The Android variant of Swift may be built using the following `build-script`
invocation:
```
$ utils/build-script \
-R \ # Build in ReleaseAssert mode.
--android \ # Build for Android.
--android-ndk ~/android-ndk-r10e \ # Path to an Android NDK.
--android-ndk-version 21 \
--android-icu-uc ~/libicu-android/armeabi-v7a/libicuuc.so \
--android-icu-uc-include ~/libicu-android/armeabi-v7a/icu/source/common \
--android-icu-i18n ~/libicu-android/armeabi-v7a/libicui18n.so \
--android-icu-i18n-include ~/libicu-android/armeabi-v7a/icu/source/i18n/
```
Android builds have the following dependencies, as can be seen in
the build script invocation:
1. An Android NDK of version 21 or greater, available to download
here: http://developer.android.com/ndk/downloads/index.html.
2. A libicu compatible with android-armv7.
Introduce DarwinPlatformKind, which would allow us to switch on darwin
platforms instead of copying and pasting the brittle logic in several places.
Use the helper method to simplify ClangImporter.
We already do for the iOS simulator and the tvOS simulator. This fixes
the 'unrecognized selector sent to instance’ bridging crashes in the stdlib
watch simulator tests.
Greg Parker did the hard work of tracking this down and suggested the fix.
<rdar://problem/20932146>
Swift SVN r28846
- Add frontend and standard library build support for tvOS.
- Add frontend support for watchOS.
watchOS standard library builds are still disabled during SDK bring-up.
To build for TVOS, specify --tvos to build-script.
To build for watchOS, specify --watchos to build-script (not yet supported).
This patch does not include turning on full tests for TVOS or watchOS, and
will be included in a follow-up patch.
Swift SVN r26278
