Issue 5568: make build output terse by default (issue 557080043 by address@hidden)

[nine . fierce . ballads]

Reviewers: ,

Description:
https://sourceforge.net/p/testlilyissues/issues/5568/

The goal is to show progress without burying warnings and errors in
the noise of long commands.

Options VERBOSE=1 and SILENT=1 make the output more like the usual
"make" and "make -s" (respectively).

The verbosity level affects the options that are passed to some
commands, but there is room for improvement in this area.

Please review this at https://codereview.appspot.com/557080043/

Affected files (+231, -8 lines):
  M Documentation/GNUmakefile
  M Documentation/css/GNUmakefile
  M Documentation/logo/GNUmakefile
  M Documentation/ly-examples/GNUmakefile
  M Documentation/misc/GNUmakefile
  M Documentation/pictures/GNUmakefile
  M Documentation/po/GNUmakefile
  M Documentation/topdocs/GNUmakefile
  M GNUmakefile.in
  M elisp/GNUmakefile
  M input/regression/lilypond-book/GNUmakefile
  M input/regression/musicxml/GNUmakefile
  M lily/GNUmakefile
  M make/abc-rules.make
  M make/doc-i18n-root-rules.make
  M make/generic-rules.make
  M make/lilypond-book-rules.make
  M make/lilypond-book-vars.make
  M make/lilypond-vars.make
  M make/ly-rules.make
  M make/lysdoc-rules.make
  M make/midi-rules.make
  M make/musicxml-rules.make
  M make/mutopia-rules.make
  M make/stepmake.make
  M mf/GNUmakefile
  M stepmake/stepmake/c++-rules.make
  M stepmake/stepmake/c-rules.make
  M stepmake/stepmake/documentation-rules.make
  M stepmake/stepmake/executable-rules.make
  M stepmake/stepmake/generic-rules.make
  M stepmake/stepmake/help2man-rules.make
  M stepmake/stepmake/library-rules.make
  M stepmake/stepmake/metafont-rules.make
  M stepmake/stepmake/metafont-vars.make
  M stepmake/stepmake/python-module-rules.make
  M stepmake/stepmake/script-rules.make
  M stepmake/stepmake/shared-library-rules.make
  M stepmake/stepmake/substitute-rules.make
  M stepmake/stepmake/test-rules.make
  M stepmake/stepmake/tex-rules.make
  M stepmake/stepmake/texinfo-rules.make
  M stepmake/stepmake/texinfo-vars.make
  M vim/GNUmakefile