fix: Use dynamic ruby even in static variants

[sgillespie]

Static shell variants are currently failing with

In file included from bigdecimal.h:14,
                 from bigdecimal.c:11:
missing.h:127:1: error: static declaration of 'rb_rational_num' follows non-static declaration
  127 | rb_rational_num(VALUE rat)
      | ^~~~~~~~~~~~~~~

But It's not important to use static ruby anyways, because we are interested in producing static artifacts, not the build tools themselves.

So, this change

• Removes static ruby in favor of the regular one
• Removes patches that fixes static ruby

[angerman]

We should document why it doesn't matter that ruby is not static. We ultimately care about producing static outputs, not that the build tools closure is necessarily static.