autogen.sh support for automake-1.11

[Emess]

Quite a few linux distributions are on automake 1.11 already such as gentoo, arch, and debian, and as such users of these distributions are required to patch autogen.sh just to have it not fail on reading what version of automake is installed.

The following is an example of what happens:

checking for automake >= 1.9 ...
  You must have automake 1.9 or newer installed to compile aegisub.
  Download the appropriate package for your distribution,
  or get the source tarball at ftp://ftp.gnu.org/pub/gnu/automake/

./autogen.sh: line 151: automake-1.9: command not found
Major version might be too new (1.9)

This appears to be due to a slight error in the way the autogen.sh script itself is written, as there should be a catchall for any automake binary without a version in the filename, however the variable is not set correctly and this check gets skipped. The options left to the script are for automake 1.10 and 1.9 respectively, neither of which work. I do not understand enough of autoconf to fix this properly but a check similar to what autoconf does in the autogen.sh script should work fine. Additionally, the script returns that the major version, as opposed to the minor, is too big, which is either a typo or flawed logic on it's part.

Until someone fixes it properly, I am submitting a patch that adds 1.11 functionality to the script.

[Emess]

Patch for Automake-1.11 functionality for autogen.sh

[verm]

(In [3862]) Commit a different patch than the one in #1064.. this sets the default automake required version to 1.10.. the detection for 1.11 is *after* 1.11 because we prefer to use that, though we do prefer to use 1.11 than 1.9 if it's available. Updates #1064

[verm]

(In [3863]) Merge r3862, updates #1064.

[verm]

I tried to reproduce the autodetection failure on Freebsd, Ubuntu and OSX I couldn't. I'm going to close this as resolved until someone else comes up with a similar error.