title: How do you disable the unused variable warnings coming out of gcc in 3rd party code I do not wish to edit?
body: <p>I'd like to know what switch you pass to the gcc compiler to turn off unused variable warnings?  I'm getting errors out of boost on windows and I do not want to touch the boost code:</p>
  
  <pre><code>C:\boost_1_52_0/boost/system/error_code.hpp: At global scope:
  C:\boost_1_52_0/boost/system/error_code.hpp:214:36: error: 'boost::system::posix_category' defined but not used [-Werror=unused-variable]
  C:\boost_1_52_0/boost/system/error_code.hpp:215:36: error: 'boost::system::errno_ecat' defined but not used [-Werror=unused-variable]
  C:\boost_1_52_0/boost/system/error_code.hpp:216:36: error: 'boost::system::native_ecat' defined but not used [-Werror=unused-variable]
  </code></pre>
  
  <p>I tried using both <code>-Wunused-value</code> and <code>-Wno-unused-value</code> but neither suppressed the messages above.</p>
  
  <p>What is the right command, here is my compile line:</p>
  
  <pre><code>g++  -g -fno-inline -Wall -Werror -Wextra -Wfloat-equal -Wshadow
  -Wpointer-arith -Wcast-qual -Wcast-align -Wwrite-strings -Wno-conversion 
  -Wdisabled-optimization -Wredundant-decls -Wunused-value -Wno-deprecated 
  -IC:\\boost_1_52_0 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 
  -c -o op.o op.cpp
  </code></pre>
  
  <p>Perhaps the <code>-Wall</code> overrides my goal?</p>