[README.md] add guide for OS X

"AC_LIB_PREPARE_PREFIX is m4_require'd but not m4_defun'd" 
This macro is GNU specific and won't compile with OS X gettext.
[config.c] use intmax_t to fix warning across platforms

fixes:
  config.c:186:56: warning: format specifies type 'long' but the argument
    has type 'uint64_t' (aka 'unsigned long long') [-Wformat]
    err("error parsing %s at %ld near:", filename, whence);
Merge pull request #132 from ChrisLundquist/fix-printf-warning

[config.c] fix printf format string warning
[README.md] add guide for OS X

Fix formatting and call our `AC_LIB_HAVE_LINKFLAGS`
[address.c] more idiomatic unused result in is_numeric()
[address.c] fix unitialized length in memcmp()
[listener.c] log listener address to logger rather than stderr
Merge pull request #131 from ChrisLundquist/patch-2

[README.md] add guide for OS X
Dual stack DNS resolver
resolver: configuration support for DNS resolver
travis-ci: do not try to sign test package build
Update TODO: nameserver config implemented
Fix path to autogen.sh
travis-ci: do not try to sign test package build
Merge pull request #137 from thomasnordquist/patch-1

Fix path to autogen.sh
Merge pull request #136 from dlundquist/dual-stack-resolver

Dual stack resolver
Fix Spelling Mistakes
Merge pull request #139 from imlonghao/master

Fix Spelling Mistakes