Re: [PATCH] configure: add support for psuedo-"in source tree" builds

[Peter Maydell]

On Thu, 20 Aug 2020 at 17:56, Daniel P. Berrangé <berrange@redhat.com> wrote:
> Meson requires the build dir to be separate from the source tree. Many
> people are used to just running "./configure && make" though and the
> meson conversion breaks that.
>
> This introduces some backcompat support to make it appear as if an
> "in source tree" build is being done, but with the the results in the
> "build/" directory. This allows "./configure && make" to work as it
> did historically, albeit with the output binaries staying under build/.

> +if test "$PWD" == "$source_path"
> +then
> +    echo "Using './build' as the directory for build output"
> +    rm -rf build
> +    mkdir -p build

Can we put in a mollyguard here so we only blow away build/
if we previously auto-created it? Something like

      if ! -e build || -e build/created-by-configure; then
          rm -rf build
          mkdir -p build
          touch build/created-by-configure
      else
          echo "some helpful error message here"
      fi

(shell syntax probably wrong but you get the idea)

My current setup has multiple build-directories like
build/x86, build/clang, ... and I'd like a guard against
configure blowing them all away if I accidentally run it
from the source tree some day.

thanks
-- PMM