Various processes run as part of make all for typical projects will
end up giving output full of replacement characters, or crashing, if run
in an ASCII locale. Explicitly run them in a UTF-8 locale to avoid that.
This assumes (I haven’t verified) that the code in Builder which parses
the make all output is UTF-8–safe.
See glib#1430.
Signed-off-by: Philip Withnall withnall@endlessm.com