This makes the node_crypto module available for node built using just a default OS X dev environment (no darwinports or fink).
Also on other platforms use -pthread for compiling commands not just linking because I noticed in the gcc(1) man page -pthread Adds support for multithreading with the pthreads library. This option sets flags for both the preprocessor and linker. Removing the errno check in deps/coupling because it was a hack (e165859) added to fix stdio problems. Without adding -threads, errno is not thread local, and coupling was not correctly checking the errno. It appears -mt does nothing to gcc/solaris.
…braries and headers.