How to suppress GCC warnings from library headers?

I found the trick. For library includes, instead of -Idir use -isystem dir in the makefile. GCC then treats boost etc. as system includes and ignores any warnings from them.

For those using CMake, you can modify your include_directories directives to include the symbol SYSTEM which suppresses warnings against such headers.

include_directories(SYSTEM "${LIB_DIR}/Include")
                    ^^^^^^

You can use pragmas. For example:

// save diagnostic state
#pragma GCC diagnostic push 

// turn off the specific warning. Can also use "-Wall"
#pragma GCC diagnostic ignored "-Wunused-but-set-variable"

#include <boost/uuid/uuid.hpp>
#include <boost/uuid/uuid_generators.hpp>
#include <boost/uuid/uuid_io.hpp>
#include <boost/lexical_cast.hpp>

// turn the warnings back on
#pragma GCC diagnostic pop

You may try to include library headers using -isystem instead of -I. This will make them "system headers" and GCC won't report warnings for them.