preConfigureScript autogen.sh error: 'configure.ac' is required

I get a project, and this is my settings.json:

{
    "makefile.preConfigureScript": "${workspaceFolder}/autogen.sh",
    // I also tried the below, but the same error.
    // "makefile.preConfigureScript": "./autogen.sh",
}

Then, I click Makefile: Pre-Configure, but thes is error:

Pre-configuring...
Script: "/home/xxx/xf86-video-dummy/autogen.sh"
/home/xxx/xf86-video-dummy
/bin/bash
/bin
autoreconf: export WARNINGS=
autoreconf: error: 'configure.ac' is required
The pre-configure script failed. This project may not configure successfully.

If I run cd /home/xxx/xf86-video-dummy && ./autogen.sh, it indeed works.

there is autogen.sh, for test I modify it:

#! /bin/sh
   # run in terminal: /home/xxx/xf86-video-dummy
   # run in vscode: /home/xxx/xf86-video-dummy
   pwd
   # run in terminal: ./autogen.sh
   # run in vscode: /bin/bash
   echo $0

srcdir=`dirname "$0"`
   # run in terminal: .
   # run in vscode: /bin
   echo ${srcdir}

test -z "$srcdir" && srcdir=.

ORIGDIR=`pwd`
cd "$srcdir"

autoreconf -v --install || exit 1     # error in this line.
cd "$ORIGDIR" || exit $?

git config --local --get format.subjectPrefix >/dev/null 2>&1 ||
    git config --local format.subjectPrefix "PATCH xf86-video-dummy"

if test -z "$NOCONFIGURE"; then
    exec "$srcdir"/configure "$@"
fi

I think this about work path or something about path, but I search a lot, still do not fix it.

Start with the Makefile: Pre-Configure entry point and the makefile.preConfigureScript setting, then reproduce the issue using the shown settings.json and autogen.sh. Compare the working directory and script path in the VS Code run with the terminal run; done means the pre-configure command finds configure.ac and completes successfully.