cc -g -o dump1090 dump1090.o anet.o  -L -lrtlsdr -lpthread -lm
/usr/bin/ld: dump1090.o: in function `modesInitRTLSDR':
/home/julien/Downloads/dump1090-master/dump1090.c:340: undefined reference to `rtlsdr_get_device_count'
/usr/bin/ld: /home/julien/Downloads/dump1090-master/dump1090.c:348: undefined reference to `rtlsdr_get_device_usb_strings'
/usr/bin/ld: /home/julien/Downloads/dump1090-master/dump1090.c:353: undefined reference to `rtlsdr_open'
/usr/bin/ld: /home/julien/Downloads/dump1090-master/dump1090.c:360: undefined reference to `rtlsdr_set_tuner_gain_mode'
/usr/bin/ld: /home/julien/Downloads/dump1090-master/dump1090.c:372: undefined reference to `rtlsdr_set_tuner_gain'
/usr/bin/ld: /home/julien/Downloads/dump1090-master/dump1090.c:377: undefined reference to `rtlsdr_set_freq_correction'
/usr/bin/ld: /home/julien/Downloads/dump1090-master/dump1090.c:379: undefined reference to `rtlsdr_set_center_freq'
/usr/bin/ld: /home/julien/Downloads/dump1090-master/dump1090.c:380: undefined reference to `rtlsdr_set_sample_rate'
/usr/bin/ld: /home/julien/Downloads/dump1090-master/dump1090.c:381: undefined reference to `rtlsdr_reset_buffer'
/usr/bin/ld: /home/julien/Downloads/dump1090-master/dump1090.c:383: undefined reference to `rtlsdr_get_tuner_gain'
/usr/bin/ld: /home/julien/Downloads/dump1090-master/dump1090.c:378: undefined reference to `rtlsdr_set_agc_mode'
/usr/bin/ld: /home/julien/Downloads/dump1090-master/dump1090.c:368: undefined reference to `rtlsdr_get_tuner_gains'
/usr/bin/ld: dump1090.o: in function `readerThreadEntryPoint':
/home/julien/Downloads/dump1090-master/dump1090.c:460: undefined reference to `rtlsdr_read_async'
/usr/bin/ld: dump1090.o: in function `main':
/home/julien/Downloads/dump1090-master/dump1090.c:2632: undefined reference to `rtlsdr_close'
collect2: error: ld returned 1 exit status
make: *** [Makefile:12: dump1090] Error 1

$ apt search librtlsdr
Sorting... Done
Full Text Search... Done
gr-osmosdr/testing,now 0.1.4-14+b10 amd64 [installed,automatic]
  Gnuradio blocks from the OsmoSDR project

librtlsdr-dev/testing,now 0.6-1 amd64 [installed]
  Software defined radio receiver for Realtek RTL2832U (development)

librtlsdr0/testing,now 0.6-1 amd64 [installed]
  Software defined radio receiver for Realtek RTL2832U (library)