Switch compilers when no build is specified

Given the current state of OS X compilers, the original fails_with
behavior is becoming less useful, mostly resulting in build failures
each time the compiler is updated. So make the following changes:

When a build is specified, we retain the old behavior: switch compilers
if the available compiler is <= the build, don't switch if it is > the
build.

When no build is specified, unconditionally switch compilers, and don't
output the advice message. This allows us to mark formulae as
perpetually failing, avoiding the need to update formulae each time a
new compiler build is made available.

As a bonus, this makes the logic much easier to reason about.

Closes #18175.
stunnel 4.55

Closes #18434.
ec2-api-tools 1.6.7

Closes #18436.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
ec2-ami-tools 1.4.0.9

 - adopt url format from ec2-api-tools

Closes #18435.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
highlight compilation fix on case-sensitive OS

The formula applies a patch on the Makefile.
The patch was applied on the file named src/Makefile
However, the file is actually named src/makefile

Closes #18437.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
exiftool 9.23
opam 0.9.6

Closes #18443.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
RabbitMQ 3.0.4

Closes #18444.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
mariadb 5.5.30

Closes #18445.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
tuntap: fix install instructions

Add suggestion to change startup items owner during manual installation
to root:wheel.

Closes #18439.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
Blacklist plain gcc formula with caveat pointing to homebrew-versions

Closes #17911.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
node: formatting
libffi: add test
jenkins 1.505

Closes #18447.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
ruby-build: add autoconf and pkg-config deps.

When compiling ruby versions with ruby-build (and of course, rbenv)
from a brand new Mountain Lion (10.8.2) setup and no other formulas,
the build process fails by missing autoconf and pkg-config.

Tested with ruby v2.0.0-dev and v1.9.3-p385.

Thanks to Pierre Paridans.

Closes #18016.
hexedit 1.2.13

Closes #18449.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
EditorConfig 0.11.0

Closes #18448.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
denyhosts: 10.8 has no secure.log and logs sshd to system.log

Closes #18418.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
Emacs 24.3

Closes #18391.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
doctor: mess with indentation