Simplify build.sh
these lines are probably not needed. Copied them from another recipe.
#!/usr/bin/env bash
-export CFLAGS="-O2 -g $CFLAGS"
-export CXXFLAGS="-O2 -g $CXXFLAGS"
-export LD_LIBRARY_PATH="${PREFIX}/lib:${LD_LIBRARY_PATH}"
-export DYLD_FALLBACK_LIBRARY_PATH="${PREFIX}/lib:${DYLD_FALLBACK_LIBRARY_PATH}"
-
if [ "$(uname)" == "Darwin" ]; then
CXXFLAGS="$CXXFLAGS -fno-common"
fi
