Merge branch 'mbedtls-1.3' into development

* mbedtls-1.3:
  Actually use armcc for the armcc test ^^'
  Add more -O level variety in all.sh
  Document recent make changes
  build: Makefile: cleanup CFLAGS
  build: Makefile: cleanup LDFLAGS
  build: Makefile: simplify root Makefile
  build: Makefile: remove bashism

Conflicts:
	programs/Makefile