title: Undefined references to math.h even though it is linked while using a makefile in liquid-dsp library
body: <p>I'm reposting this <a href="https://github.com/jgaeddert/liquid-dsp/issues/284" rel="nofollow noreferrer">issue</a> in Github in order to get more visibility.</p>
  <p>Basically I'm trying to use liquid-dsp, I've already run the &quot;make&quot; command and it was successful, eventually.</p>
  <p>But now I'm trying to run &quot;make examples&quot; as explained in &quot;<a href="https://github.com/jgaeddert/liquid-dsp#examples" rel="nofollow noreferrer">Installation</a>&quot; but I keep getting this error:</p>
  <pre><code>choza@chozaUbuntu:~/Documents/liquid-dsp$ make examples
  gcc -lfec -lfftw3f -lc -lm   examples/agc_example.o libliquid.a   -o examples/agc_example
  /usr/bin/ld: examples/agc_example.o: in function `main':
  /home/choza/Documents/liquid-dsp/examples/agc_example.c:71: undefined reference to `powf'
  /usr/bin/ld: /home/choza/Documents/liquid-dsp/examples/agc_example.c:94: undefined reference to `cexpf'
  /usr/bin/ld: /home/choza/Documents/liquid-dsp/examples/agc_example.c:101: undefined reference to `cosf'
  /usr/bin/ld: /home/choza/Documents/liquid-dsp/examples/agc_example.c:103: undefined reference to `cosf'
  /usr/bin/ld: /home/choza/Documents/liquid-dsp/examples/agc_example.c:107: undefined reference to `powf'
  /usr/bin/ld: /home/choza/Documents/liquid-dsp/examples/agc_example.c:158: undefined reference to `log10f'
  /usr/bin/ld: /home/choza/Documents/liquid-dsp/examples/agc_example.c:157: undefined reference to `log10f'
  /usr/bin/ld: /home/choza/Documents/liquid-dsp/examples/agc_example.c:156: undefined reference to `log10f'
  /usr/bin/ld: /home/choza/Documents/liquid-dsp/examples/agc_example.c:155: undefined reference to `log10f'
  /usr/bin/ld: libliquid.a(agc_crcf.o): in function `agc_crcf_print':
  /home/choza/Documents/liquid-dsp/src/agc/src/agc.c:134: undefined reference to `log10'
  /usr/bin/ld: libliquid.a(agc_crcf.o): in function `agc_crcf_set_bandwidth':
  /home/choza/Documents/liquid-dsp/src/agc/src/agc.c:220: undefined reference to `sqrtf'
  /usr/bin/ld: libliquid.a(agc_crcf.o): in function `agc_crcf_squelch_set_threshold':
  /home/choza/Documents/liquid-dsp/src/agc/src/agc.c:354: undefined reference to `powf'
  /usr/bin/ld: libliquid.a(agc_crcf.o): in function `agc_crcf_squelch_get_threshold':
  /home/choza/Documents/liquid-dsp/src/agc/src/agc.c:361: undefined reference to `log10f'
  /usr/bin/ld: libliquid.a(agc_crcf.o): in function `agc_crcf_estimate_input_energy':
  /home/choza/Documents/liquid-dsp/src/agc/src/agc.c:399: undefined reference to `sqrtf'
  /usr/bin/ld: libliquid.a(agc_crcf.o): in function `agc_crcf_estimate_gain_log':
  /home/choza/Documents/liquid-dsp/src/agc/src/agc.c:431: undefined reference to `powf'
  /usr/bin/ld: libliquid.a(agc_crcf.o): in function `agc_crcf_estimate_gain_true':
  /home/choza/Documents/liquid-dsp/src/agc/src/agc.c:477: undefined reference to `sqrtf'
  /usr/bin/ld: libliquid.a(randn.o): in function `randnf':
  /home/choza/Documents/liquid-dsp/src/random/src/randn.c:44: undefined reference to `logf'
  /usr/bin/ld: /home/choza/Documents/liquid-dsp/src/random/src/randn.c:44: undefined reference to `sinf'
  /usr/bin/ld: /home/choza/Documents/liquid-dsp/src/random/src/randn.c:44: undefined reference to `sqrtf'
  /usr/bin/ld: libliquid.a(randn.o): in function `crandnf':
  /home/choza/Documents/liquid-dsp/src/random/src/randn.c:66: undefined reference to `logf'
  /usr/bin/ld: /home/choza/Documents/liquid-dsp/src/random/src/randn.c:66: undefined reference to `cexpf'
  /usr/bin/ld: /home/choza/Documents/liquid-dsp/src/random/src/randn.c:66: undefined reference to `sqrtf'
  /usr/bin/ld: libliquid.a(randn.o): in function `randnf_pdf':
  /home/choza/Documents/liquid-dsp/src/random/src/randn.c:95: undefined reference to `expf'
  /usr/bin/ld: /home/choza/Documents/liquid-dsp/src/random/src/randn.c:95: undefined reference to `sqrtf'
  /usr/bin/ld: libliquid.a(randn.o): in function `randnf_cdf':
  /home/choza/Documents/liquid-dsp/src/random/src/randn.c:103: undefined reference to `erff'
  collect2: error: ld returned 1 exit status
  make: *** [&lt;builtin&gt;: examples/agc_example] Error 1
  </code></pre>
  <p>I've already tried to modify the makefile, I do know that the linker flag &quot;-lm&quot; should be added at the end of the command, and it is.</p>