A long time ago, after a full build built the compiler, it would then use
the result to rebuild itself. This was to ensure that errors did not
result in bulding a bad compiler (that would only be detected in the next
full build). Somehow this functionality was deleted, although it was being
done in Appveyor.
I have now, with the latest merge of PR 1247 restored that. You can now be
more confident in full builds (including on Travis), although they may
take a minute longer.
Timothy C. Lethbridge, PhD, P.Eng., I.S.P., CSDP
Professor of Software Engineering and Computer Science
/ Professeur Titulaire de génie logiciel et d'informatique
Faculté de genie / Faculty of Engineering
University of Ottawa / Université d'Ottawa