Add link flags from pkg-config for libusb-1.0

[mikeage]

Needed when using Mac OS X 10.11, with libusb installed through homebrew

[yuvadm]

On Linux I'm getting:

$ pkg-config --libs librtlsdr
-lrtlsdr -lusb-1.0

Is this not the case on OS X 10.11?

[mikeage]

I do have the lib, but I'm missing the path.

$ pkg-config --libs libusb-1.0
-L/usr/local/Cellar/libusb/1.0.20/lib -lusb-1.0
$ pkg-config --libs librtlsdr
-L/usr/local/Cellar/librtlsdr/0.5.3/lib -lrtlsdr -lusb-1.0

If we had -L/usr/local/lib, that would also be good enough, but this is not in the default search path for libs.

[yuvadm]

On OS X 10.9 I get:

$ pkg-config --libs librtlsdr
-L/usr/local/Cellar/librtlsdr/0.5.3/lib -lrtlsdr -lusb-1.0

and a successful build. Are you sure this isn't a local issue? Does this repro on other 10.11 boxes?

Also check:

$ pkg-config --cflags librtlsdr
-I/usr/local/Cellar/librtlsdr/0.5.3/include/ -I/usr/local/Cellar/libusb/1.0.18/include/libusb-1.0

[mikeage]

I don't have any other machines to test on. Where does your OS X machine have libusb-1.0.*? I didn't have it in /usr/local/Cellar/librtlsdr/0.5.3/lib, but only in /usr/local/Cellar/libusb/1.0.20/lib.

[yuvadm]

I have libusb in the same location (granted, version 1.0.18)

[mikeage]

Interesting. I'll poke around in the homebrew recipe a bit later to see if I can see what's going on.

[mikeage]

No clue. Doesn't seem like an earlier version of the recipe would have done this, nor does building from source. Maybe some version of the bottle included it; can I ask what you get if you remove and reinstall librtlsdr? (not sure how much time / effort you want to put into this...)

[mikeage]

FWIW, the root cause seems to be https://www.mail-archive.com/osmocom-sdr@lists.osmocom.org/msg00955.html . I recently replaced homebrew's librtlsdr with https://github.com/keenerd/rtl-sdr, where it has this fix (see keenerd/rtl-sdr@bc872cb) , and now pkg-config --libs librtlsdr returns a -L for libusb-1.0 as well.

[yuvadm]

@mikeage great news! Can we consider this issue closed? Or is there anything you think we should change (only if it won't break other environments, of course)?

[mikeage]

Given that the "official" homebrew version seems to be broken, out of the box, I'm not sure it's really closed. dump1090 does depend on both libusb-1.0 and librtlsdr, and even if one often includes the other, I think it's more proper to include an explicit dependency. I presume pkg-config --libs libusb-1.0 doesn't break anything on Linux, does it?

OTOH, most packages that use librtlsdr don't include libusb-1.0, and I've had to patch all of them as well. I understand the forks of dump1090, but I've seen others as well, so maybe I'm missing something. Or maybe most users are on Linux :)

[JoeMatt]

This worked for me on OS X 14.0 ARM

CC?=clang
CFLAGS?=-O2 -g -Wall -W $(shell pkg-config --cflags librtlsdr)

LDLIBS+= \
 $(shell pkg-config --libs libusb-1.0) \
 $(shell pkg-config --libs librtlsdr) \
 -lpthread \
 -lm

PROGNAME=dump1090

all: $(PROGNAME)

%.o: %.c
	$(CC) $(CFLAGS) -c $<

dump1090: $(PROGNAME).o anet.o
	$(CC) -g -o $(PROGNAME) $(PROGNAME).o anet.o $(LDFLAGS) $(LDLIBS)

clean:
	rm -f *.o $(PROGNAME)