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>

scripts/make-config-poison.sh

@@ -0,0 +1,16 @@
+#! /bin/sh
+
+if test $# = 0; then
+  exit 0
+fi
+
+# Create list of config switches that should be poisoned in common code...
+# but filter out CONFIG_TCG and CONFIG_USER_ONLY which are special.
+exec sed -n \
+  -e' /CONFIG_TCG/d' \
+  -e '/CONFIG_USER_ONLY/d' \
+  -e '/^#define / {' \
+  -e    's///' \
+  -e    's/ .*//' \
+  -e    's/^/#pragma GCC poison /p' \
+  -e '}' "$@"