[notmuch] [PATCH] Makefile: Magic silent rules.

[Chris Wilson]

Use the facilities of GNU make to create a magic function that will
on the first invocation print a description of how to enable verbose
compile lines and then print the quiet rule.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Signed-off-by: Carl Worth <cworth at cworth.org>
Cc: Mikhail Gusarov <dottedmag at dottedmag.net>
---
 Makefile           |   18 +++++++++++++++---
 Makefile.local     |    2 +-
 lib/Makefile.local |    2 +-
 3 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/Makefile b/Makefile
index 0411cbb..96fcdd5 100644
--- a/Makefile
+++ b/Makefile
@@ -28,14 +28,26 @@ include lib/Makefile.local
 # And get user settings from the output of configure
 include Makefile.config
 
+# The user has not set any verbosity, default to quiet mode and inform the
+# user how to enable verbose compiles.
+ifeq ($(V),)
+quiet_DOC := "Use \"$(MAKE) V=1\" to see the verbose compile lines.\n"
+quiet = @echo $(quiet_DOC)$(eval quiet_DOC:=)"  $1	$@";
+endif
+# The user has explicitly enabled quiet compilation.
+ifeq ($(V),0)
+quiet = @echo "  $1	$@";
+endif
+# Otherwise, print the full command line.
+
 %.o: %.cc
-	$(CXX) -c $(CFLAGS) $(CXXFLAGS) $< -o $@
+	$(call quiet,CXX) $(CXX) -c $(CFLAGS) $(CXXFLAGS) $< -o $@
 
 %.o: %.c
-	$(CC) -c $(CFLAGS) $< -o $@
+	$(call quiet,CC) $(CC) -c $(CFLAGS) $< -o $@
 
 %.elc: %.el
-	emacs -batch -f batch-byte-compile $<
+	$(call quiet,EMACS) emacs -batch -f batch-byte-compile $<
 
 .deps/%.d: %.c
 	@set -e; rm -f $@; mkdir -p $$(dirname $@) ; \
diff --git a/Makefile.local b/Makefile.local
index ecd4ceb..115de0e 100644
--- a/Makefile.local
+++ b/Makefile.local
@@ -20,7 +20,7 @@ notmuch_client_srcs =		\
 
 notmuch_client_modules = $(notmuch_client_srcs:.c=.o)
 notmuch: $(notmuch_client_modules) lib/notmuch.a
-	$(CXX) $^ $(LDFLAGS) -o $@
+	$(call quiet,CXX) $(CXX) $^ $(LDFLAGS) -o $@
 
 notmuch.1.gz: notmuch.1
 	gzip --stdout notmuch.1 > notmuch.1.gz
diff --git a/lib/Makefile.local b/lib/Makefile.local
index 79f7b0b..f635da7 100644
--- a/lib/Makefile.local
+++ b/lib/Makefile.local
@@ -18,7 +18,7 @@ libnotmuch_cxx_srcs =		\
 
 libnotmuch_modules = $(libnotmuch_c_srcs:.c=.o) $(libnotmuch_cxx_srcs:.cc=.o)
 $(dir)/notmuch.a: $(libnotmuch_modules)
-	$(AR) rcs $@ $^
+	$(call quiet,AR) $(AR) rcs $@ $^
 
 SRCS  := $(SRCS) $(libnotmuch_c_srcs) $(libnotmuch_cxx_srcs)
 CLEAN := $(CLEAN) $(libnotmuch_modules) $(dir)/notmuch.a
-- 
1.6.5.3