Revert bogus bug fix that prevented the deployment of v3.6.7 at first

[dscho]

When I tried to deploy Git for Windows' MSYS2 runtime v3.6.7, it failed the CI build with a really unhelpful:

        [...]
        GEN      tlsoffsets
      <stdin>:6:37: error: expected initializer before '*' token
      <stdin>:6:41: error: expected unqualified-id before '=' token
      <stdin>:6:71: error: expected unqualified-id before ')' token
      awk: fatal: cannot open file `tlsoffsets' for reading: No such file or directory
      /d/a/MSYS2-packages/MSYS2-packages/msys2-runtime/src/msys2-runtime/winsup/cygwin/scripts/gentls_offsets: line 104: [: -ne: unary operator expected

This despite the fact that MSYS2's own MSYS2 runtime v3.6.7 deployed just fine. The reason is that the gawk update to v5.4.0 unveiled an erroneous bug fix that Git for Windows still carries. The part of the build that was failing was where it generated the tlsoffsets file. Over the course of a day, I reduced this to a small reproducer. In particular, with LC_ALL=C the following invocation:

printf 'void (*func) (int, siginfo_t *, void *);\n' |
gawk '
  {
      # Filter out function names
      print gensub (/\(\*(\w+)\)\s*\([^\)]*\)/, "\\1", "g");
  }
'

does not print the expected:

void func;

but instead:

void (*func) (int, siginfo_t *, void *);

I did verify that reverting the bug fix lets the build succeed again, and that it does not regress on git-for-windows/git#2189: scripts with umlauts in their filenames can still be executed via double-clicking even after reverting. So let's do that.

As a very nice bonus, it reduces the divergence between MSYS2's and Git for Windows' variant of the MSYS2 runtime.