build: enable AM_SILENT_RULES

This shuts up make by default (can be reversed with "make V=1" or
--disable-silent-rules).  This is useful since warnings and error
messages become more visible with less noise.

Tested on Linux with GNU make and FreeBSD with system's BSD make.

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
Acked-by: Paul Jakma <paul@jakma.org>
1 file changed