New port mksh

[Schamschula (Marius Schamschula)]

I've put together a Portfile for mksh:

A free implementation of the Korn Shell programming language and a successor to the Public Domain Korn Shell (pdksh).

[ryandesign (Ryan Carsten Schmidt)]

Thanks. Some observations:

• You shouldn't usually set build.cmd to multiple commands. Since your goal is to set the execute bit of the build script before running it, set "build.cmd ./Build.sh", and set the execute bit in a post-extract block using "file attributes ... -permissions".
• Instead of "${workpath}/${destdir}", use "${destroot}".
• Instead of "build.target-delete all", use "build.target".
• In the destroot block, you shouldn't specify the owner and group. When specifying the mode, we usually use 755 for executables and 644 for non-executable files.
• Because you use "use_configure no" and a custom build system, you need to add code to ensure the port is UsingTheRightCompiler and -arch flags and has a universal variant. Fortunately the build system accepts environment variables to do this.

[ryandesign (Ryan Carsten Schmidt)]

Committed with the above changes in r120262.