rtems-tools Do Not Compile on Cygwin

Summary

rtems-tools do not build on Cygwin. Multiple files fail to compile and report this:

[ 15/270] Compiling rtemstoolkit/elftoolchain/libelf/gelf_cap.c
../rtemstoolkit/elftoolchain/libelf/gelf_cap.c:36:13: error: expected declaration specifiers or ‘...’ before string constant
   36 | ELFTC_VCSID("$Id: gelf_cap.c 3977 2022-05-01 06:45:34Z jkoshy $");
      |             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Waf: Leaving directory `/home/jrs007/rtems-work/rtems-tools/build'

Steps to reproduce

Simple to reproduce -- just build on Cygwin.