build: cleanup compiler output

[jb55]

Hide our CFLAGS and LDFLAGS line noise each time an object file is compiled
or linked.

Also add a make show-flags command for displaying CC, LD, CFLAGS and
LDFLAG information. This is shown at the start of each build.

$ make

CC: gcc -DBINTOPKGLIBEXECDIR="../libexec/c-lightning" -Wall [..]
LD: gcc   -Og    -Lexternal -lwallycore -lsecp256k1 -ljsmn  [..]
...
cc ccan/ccan/crypto/shachain/shachain.c -DSHACHAIN_BITS=48
cc lightningd/test/run-jsonrpc.c
cc lightningd/test/run-invoice-select-inchan.c
cc lightningd/test/run-log-pruning.c
cc lightningd/test/run-find_my_abspath.c
cc cli/test/run-large-input.c
cc cli/test/run-remove-hint.c
ld lightningd/lightning_hsmd
ld lightningd/lightning_gossipd
ld lightningd/lightning_openingd
ld lightningd/lightning_channeld
ld lightningd/lightning_closingd
...

[cdecker]

Loving it, this will make Travis logs and other CI logs way easier to parse :-)

[rustyrussell]

Meh, got off my lawn kids!

I like being able to literally cut and paste a failing line if necessary to reproduce.

However, if we're going to do this, let's do the standard "V=1" override which shows the complete cmdline, eg:

ifeq ($V,1)
VERBOSE = echo $(2); $(2)
else
VERBOSE = echo $(1); $(2)
endif

%.o: %.c
       @$(call VERBOSE, "cc $<", $(CC) $(CFLAGS) -c -o $@ $<)

?

[jb55]

Meh, got off my lawn kids!

ok boomer

I like being able to literally cut and paste a failing line if necessary to reproduce. However, if we're going to do this, let's do the standard "V=1" override which shows the complete cmdline, eg:

alternatively we could just print the show-flags at the end if it's too much to scroll up a bit. It's not too hard to add the V=1 thing so I'll just do that for now.

[rustyrussell]

Meh, got off my lawn kids!
ok boomer

:)

I like being able to literally cut and paste a failing line if necessary to reproduce. However, if we're going to do this, let's do the standard "V=1" override which shows the complete cmdline, eg:
alternatively we could just print the show-flags at the end if it's too much to scroll up a bit. It's not too hard to add the V=1 thing so I'll just do that for now.

Yeah, but "you can construct the line" is not the same as "you can literally cut & paste it" since some lines are subtly different.

Also, 'Changelog-Changed: build: default compile output is prettier and much less verbose'?

[jb55]

@rustyrussell done

[cdecker]

ACK 6c56607