Provided an implementation for gai_strerror and gave getaddrinfo sensible default behaviour when hints is set to NULL. Ideally getaddrinfo should supply multiple addrinfo values when hints is NULL or ai_family is set to AF_UNSPEC but this is a somewhat more complex proposition
Changed library.js line 7509 to use hint !== 0 test vice hint != 0
bump EMSCRIPTEN_VERSION in tools/shared.py to 1.7.3
Replaced loop in gai_strerror with writeAsciiToMemory call and made the comment around  hopefully a little more descriptive
Merge pull request #1774 from fadams/fix-getaddrinfo-null-hints

Provided an implementation for gai_strerror and gave getaddrinfo sensibl...