-lc++ can cause link error on some systems and is not necessary on gcc 4.6+ so remove the link option and document how to build for gcc 4.4

TEST=CC=gcc-4.4 CXXFLAGS=-fno-exceptions CXX=g++-4.4 make -f linux.mk clean all
BUG=libyuv:616

Review URL: https://codereview.chromium.org/2126703003 .