fix: use alias for shasum if sha1sum is found instead

Some linux distributions might have sha1sum command available
but shasum might be missing. This will create an alias for shasum
to use sha1sum if available.

run_build_tool.sh

@@ -42,6 +42,12 @@ void main(List<String> args) {
 }
 EOF
 
+# Create alias for `shasum` if it does not exist and `sha1sum` exists
+if ! [ -x "$(command -v shasum)" ] && [ -x "$(command -v sha1sum)" ]; then
+  shopt -s expand_aliases
+  alias shasum="sha1sum"
+fi
+
 # Dart run will not cache any package that has a path dependency, which
 # is the case for our build_tool_runner. So instead we precompile the package
 # ourselves.