[PATCH 1.24.1] ash: backport fix for here document issues

[Ron Yorston]

Natanael Copa wrote:
>if true; then
>cat >>confdefs.h <<_ACEOF
>#define `date`
>_ACEOF
>fi
>
>Seems like `command` inside heredoc inside if .. fi is needed to trigger it.

Using $(command) seems to be a workaround.

Ron