tools: Add an environment variable MICROPY_MAINTAINER_BUILD.

This allows us to have some things which are fatal errors in CI or nightly
builds, but warnings in normal developer builds.

This work was funded through GitHub Sponsors.

Signed-off-by: Angus Gratton <angus@redyak.com.au>

Author: projectgus

tools/autobuild/autobuild.sh

@@ -48,6 +48,9 @@ git -C ${MICROPY_AUTOBUILD_MICROPYTHON_REPO}/lib/pico-sdk submodule update --ini
 ########################################
 # Build all firmware
 
+# Fail on some things which are warnings otherwise
+export MICROPY_MAINTAINER_BUILD=1
+
 pushd ${MICROPY_AUTOBUILD_MICROPYTHON_REPO}
 
 # build cross compiler

tools/ci.sh

@@ -9,6 +9,9 @@ fi
 # Ensure known OPEN_MAX (NO_FILES) limit.
 ulimit -n 1024
 
+# Fail on some things which are warnings otherwise
+export MICROPY_MAINTAINER_BUILD=1
+
 ########################################################################################
 # general helper functions