Create separate WASI_SDK_URL var

Author: MaxDesiatov

utils/webassembly/macos/install-dependencies.sh

@@ -13,8 +13,10 @@ cd $SWIFT_PATH
 
 cd $SOURCE_PATH
 
+WASI_SDK_URL="https://github.com/swiftwasm/wasi-sdk/releases/download/0.2.0-swiftwasm/dist-macos-latest.tgz.zip"
+
 [ ! -e dist-wasi-sdk.tgz.zip ] && \
-  wget -O dist-wasi-sdk.tgz.zip "https://github.com/swiftwasm/wasi-sdk/releases/download/0.2.0-swiftwasm/dist-macos-latest.tgz.zip"
+  wget -O dist-wasi-sdk.tgz.zip $WASI_SDK_URL
 unzip -u dist-wasi-sdk.tgz.zip -d .
 WASI_SDK_TAR_PATH=$(find . -type f -name "wasi-sdk-*")
 WASI_SDK_FULL_NAME=$(basename $WASI_SDK_TAR_PATH -macos.tar.gz)