title: clang: error: -lm: 'linker' input unused while compiling on MacOSX
body: <p>I am trying to compile a program mafTools on MacOSX using gnu make. I get the following error:</p>
  
  <pre><code>cd mafExtractor &amp;&amp; make all
  
  clang -std=c99 -stdlib=libstdc++ -O3 -c -O3 -Wall -Werror --pedantic -funroll-loops -DNDEBUG -Wshadow -Wpointer-arith -Wstrict-prototypes -Wmissing-prototypes -I ../../sonLib/lib -I ../inc -I ../external  src/mafExtractorAPI.c -o src/mafExtractorAPI.o.tmp -lm
  </code></pre>
  
  <p>This gives the error:</p>
  
  <pre><code>clang: error: -lm: 'linker' input unused [-Werror,-Wunused-command-line-argument]
  make[1]: \*** [src/mafExtractorAPI.o] Error 1
  make: \*** [mafExtractor.all] Error 2
  </code></pre>
  
  <p>I looked at similar errors but couldn't fix it. Any help will be much appreciated. Thanks!</p>
  
  <p>This is the package: <a href="https://github.com/dentearl/mafTools/tree/master/mafExtractor" rel="nofollow noreferrer">https://github.com/dentearl/mafTools/tree/master/mafExtractor</a>
  Everything else here compiled successfully.</p>
  
  <p>This is the makefile:
  <a href="https://github.com/dentearl/mafTools/blob/master/mafExtractor/Makefile" rel="nofollow noreferrer">https://github.com/dentearl/mafTools/blob/master/mafExtractor/Makefile</a></p>
  
  <p>Thanks a bunch.</p>