vscode: local: defconfig only when no .config

Similar to what is done in tasks.sh.

Not to call the docker twice when compiling.

While at it, add missing comment for shellcheck and ensure we are in the
right directory.

Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>

vscode/local-virtme.sh

@@ -1,6 +1,7 @@
 #! /bin/bash
 # SPDX-License-Identifier: GPL-2.0
 
+# Some functions will be called indirectly, see the 'custom' commands below.
 # shellcheck disable=SC2317
 
 export VIRTME_NO_INTERACTIVE=1
@@ -9,8 +10,12 @@ export MAKE="./.virtme.sh make"
 export SILENT_BUILD_FLAG=" "
 export SPINNER=0
 
+cd "${SCRIPT_DIR}/.." || exit 1
+
 defconfig() {
-	./.virtme.sh defconfig
+	if [ ! -f .virtme/build-clang/.config ]; then
+		./.virtme.sh defconfig
+	fi
 }
 
 case "${COMMAND}" in