Don't include opt/wasi-sdk paths in tar archive (#64)

Fixes #57

tar_from_installation.sh

@@ -1,9 +1,9 @@
 #!/usr/bin/env bash
 set -ex
 if [ -n "$1" ]; then
-	export VERSION="$1"
+    VERSION="$1"
 else
-	export VERSION=`./version.sh`
+    VERSION=`./version.sh`
 fi
 
 PKGDIR=build/wasi-sdk-$VERSION
@@ -17,8 +17,7 @@ case "$(uname -s)" in
 esac
 
 rm -rf $PKGDIR
-mkdir -p $PKGDIR/opt
-cp -R /opt/wasi-sdk $PKGDIR/opt/
-cd build &&
-tar czf wasi-sdk-$VERSION\-$MACHINE.tar.gz wasi-sdk-$VERSION &&
-tar cz -C compiler-rt -f libclang_rt.builtins-wasm32-wasi-$VERSION.tar.gz lib/wasi
+cp -R /opt/wasi-sdk $PKGDIR
+cd build
+tar czf wasi-sdk-$VERSION\-$MACHINE.tar.gz wasi-sdk-$VERSION
+tar czf libclang_rt.builtins-wasm32-wasi-$VERSION.tar.gz -C compiler-rt lib/wasi