2014-07-15: honor --quiet for bootstrapping in the Makefile.

honor --quiet for bootstrapping in the Makefile.

diff --git a/Makefile.am b/Makefile.am
--- a/Makefile.am
+++ b/Makefile.am
@@ -14,7 +14,7 @@ ChangeLog :
 
 .INTERMEDIATE: input.in.intermediate
 input.in.intermediate: ${wisp_SOURCES}
-	@abs_top_srcdir@/bootstrap.sh @abs_top_srcdir@ @guile@ @python3@
+	if $(AM_V_P); then @abs_top_srcdir@/bootstrap.sh @abs_top_srcdir@ @guile@ @python3@; else @abs_top_srcdir@/bootstrap.sh @abs_top_srcdir@ @guile@ @python3@ >/dev/null; fi
 
 .PHONY: syntaxtests.sh
 syntaxtests.sh : wisp.scm runtests.sh