ndk-multilib: Supply crt* files for all platforms.

It allows compiling binaries for another android variant on termux.

E.g. to compile for arm on aarch64 do:

clang -m32 -o 1 1.c -fuse-ld=lld -L/system/lib -B$PREFIX/arm-linux-androideabi/lib

Hopefully with the time -L and -B will be eliminated

packages/ndk-multilib/build.sh

@@ -0,0 +1,34 @@
+TERMUX_PKG_HOMEPAGE=https://developer.android.com/tools/sdk/ndk/index.html
+TERMUX_SUBPKG_DESCRIPTION="multilib binaries for cross-compilation"
+TERMUX_PKG_VERSION=$TERMUX_NDK_VERSION
+TERMUX_PKG_NO_DEVELSPLIT=yes
+TERMUX_PKG_KEEP_STATIC_LIBRARIES="true"
+TERMUX_PKG_PLATFORM_INDEPENDENT=true
+
+prepare_libs () {
+	local ARCH="$1"
+	local SUFFIX="$2"
+	local NDK_SUFFIX=$SUFFIX
+
+	if [ $ARCH = x86 ] || [ $ARCH = x86_64 ]; then
+	    NDK_SUFFIX=$ARCH
+	fi
+
+	mkdir -p $TERMUX_PKG_MASSAGEDIR/$TERMUX_PREFIX/$SUFFIX/lib
+	local BASEDIR=$NDK/platforms/android-${TERMUX_PKG_API_LEVEL}/arch-$ARCH/usr/lib
+	if [ $ARCH = x86_64 ] || [ $ARCH = mips64 ]; then BASEDIR+="64"; fi
+	cp $BASEDIR/*.o $TERMUX_PKG_MASSAGEDIR/$TERMUX_PREFIX/$SUFFIX/lib
+
+	LIBATOMIC=$NDK/toolchains/${NDK_SUFFIX}-*/prebuilt/linux-*/${SUFFIX}/lib
+	if [ $ARCH = arm64 ]; then LIBATOMIC+="64"; fi
+	cp $LIBATOMIC/libatomic.a $TERMUX_PKG_MASSAGEDIR/$TERMUX_PREFIX/$SUFFIX/lib/libatomic.a
+}
+
+termux_step_extract_into_massagedir () {
+	prepare_libs "arm" "arm-linux-androideabi"
+	prepare_libs "arm64" "aarch64-linux-android"
+	prepare_libs "x86" "i686-linux-android"
+	prepare_libs "x86_64" "x86_64-linux-android"
+	prepare_libs "mips" "mipsel-linux-android"
+	prepare_libs "mips64" "mips64el-linux-android"
+}