gcc.compile.c++ bin.v2/libs/wave/build/gcc-4.7/release/link-static/threading-multi/instantiate_re2c_lexer_str.o
gcc.compile.c++ bin.v2/libs/wave/build/gcc-4.7/release/link-static/threading-multi/token_ids.o
gcc.compile.c++ bin.v2/libs/wave/build/gcc-4.7/release/link-static/threading-multi/wave_config_constant.o
common.mkdir bin.v2/libs/wave/build/gcc-4.7/release/link-static/threading-multi/cpplexer
common.mkdir bin.v2/libs/wave/build/gcc-4.7/release/link-static/threading-multi/cpplexer/re2clex
gcc.compile.c++ bin.v2/libs/wave/build/gcc-4.7/release/link-static/threading-multi/cpplexer/re2clex/aq.o
gcc.compile.c++ bin.v2/libs/wave/build/gcc-4.7/release/link-static/threading-multi/cpplexer/re2clex/cpp_re.o
gcc.archive bin.v2/libs/wave/build/gcc-4.7/release/link-static/threading-multi/libboost_wave.a
common.copy /home/yadav/dev/cpp/boost_1.54/lib/libboost_wave.a
...failed updating 29 targets...
...updated 10797 targets...

How can I know what these 29 targets have failed and how to go about getting a clean build?

Thanks!