Issue Description:

ran:

$SWIFT_PATH/swift-android-toolchain/usr/bin/swiftc \
-v \
-tools-directory ${ANDROID_NDK_PATH}/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64/arm-linux-androideabi/bin \
-target armv7-none-linux-androideabi \
-sdk ${ANDROID_NDK_PATH}/platforms/android-21/arch-arm \
-L ${ANDROID_NDK_PATH}/sources/cxx-stl/llvm-libc++/libs/armeabi-v7a \
-L ${ANDROID_NDK_PATH}/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64/lib/gcc/arm-linux-androideabi/4.9.x \
-emit-library -o .build/armv7-none-linux-androideabi/debug/libSwiftLevelDB.so \
Sources/NSObject.swift

got:

Swift version 4.1-dev (LLVM a85c7fe628, Clang 12a3c42f5f, Swift 65f81dfe88)
Target: armv7-none-linux-android
/home/amr/swift/swift-android-toolchain/usr/bin/swift -frontend -c -primary-file Sources/NSObject.swift -target armv7-none-linux-android -disable-objc-interop -sdk /home/amr/android/android-ndk-r14b/platforms/android-21/arch-arm -color-diagnostics -parse-as-library -module-name SwiftLevelDB -o /tmp/NSObject-8f5c4e.o
swift: /home/amr/swift/llvm/tools/clang/lib/Serialization/ASTWriter.cpp:5413: DeclID clang::ASTWriter::getDeclID(const clang::Decl *): Assertion `DeclIDs.find(D)  && "Declaration not emitted)"' failed.
/home/amr/swift/swift-android-toolchain/usr/bin/swift[0x3ebcb74]
/home/amr/swift/swift-android-toolchain/usr/bin/swift[0x3ebceb6]
/lib/x86_64-linux-gnu/libpthread.so.0(+0x11390)[0x7f1355bde390]
/lib/x86_64-linux-gnu/libc.so.6(gsignal+0x38)[0x7f1354103428]
/lib/x86_64-linux-gnu/libc.so.6(abort+0x16a)[0x7f135410502a]
/lib/x86_64-linux-gnu/libc.so.6(+0x2dbd7)[0x7f13540fbbd7]
/lib/x86_64-linux-gnu/libc.so.6(+0x2dc82)[0x7f13540fbc82]
/home/amr/swift/swift-android-toolchain/usr/bin/swift[0x32fa6d9]
/home/amr/swift/swift-android-toolchain/usr/bin/swift[0x32f648d]
/home/amr/swift/swift-android-toolchain/usr/bin/swift[0x3308cff]
/home/amr/swift/swift-android-toolchain/usr/bin/swift[0x33056bc]
/home/amr/swift/swift-android-toolchain/usr/bin/swift[0x33485ca]
/home/amr/swift/swift-android-toolchain/usr/bin/swift[0x2f9ca7c]
/home/amr/swift/swift-android-toolchain/usr/bin/swift[0x3124935]
/home/amr/swift/swift-android-toolchain/usr/bin/swift[0x2f594d8]
/home/amr/swift/swift-android-toolchain/usr/bin/swift[0x2f19ce1]
/home/amr/swift/swift-android-toolchain/usr/bin/swift[0x2f23cf0]
/home/amr/swift/swift-android-toolchain/usr/bin/swift[0x3e4ce21]
/home/amr/swift/swift-android-toolchain/usr/bin/swift[0x3e4cf64]
/home/amr/swift/swift-android-toolchain/usr/bin/swift[0x3ebe32a]
/lib/x86_64-linux-gnu/libpthread.so.0(+0x76ba)[0x7f1355bd46ba]
/lib/x86_64-linux-gnu/libc.so.6(clone+0x6d)[0x7f13541d53dd]
Stack dump:
0. <eof> parser at end of file
<unknown>:0: error: unable to execute command: Aborted
<unknown>:0: error: compile command failed due to signal 6 (use -v to see invocation)