configure, meson: move config-poison.h to meson

This ensures that the file is regenerated properly whenever config-target.h
or config-devices.h files change.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

configure

@@ -3834,17 +3834,6 @@ if test -n "${deprecated_features}"; then
     echo "  features: ${deprecated_features}"
 fi
 
-# Create list of config switches that should be poisoned in common code...
-# but filter out CONFIG_TCG and CONFIG_USER_ONLY which are special.
-target_configs_h=$(ls *-config-devices.h *-config-target.h 2>/dev/null)
-if test -n "$target_configs_h" ; then
-    sed -n -e '/CONFIG_TCG/d' -e '/CONFIG_USER_ONLY/d' \
-        -e '/^#define / { s///; s/ .*//; s/^/#pragma GCC poison /p; }' \
-        $target_configs_h | sort -u > config-poison.h
-else
-    :> config-poison.h
-fi
-
 # Save the configure command line for later reuse.
 cat <<EOD >config.status
 #!/bin/sh