checksrc-all: rewrite in Perl, remove checksrc.bat

`checksrc.bat` was outdated and required Perl for `checksrc.pl` anyway.
Rewrite `checksrc-all.sh` in Perl, making it usable in envs without
a POSIX shell.

Closes #17882

Makefile.am

@@ -65,9 +65,7 @@ CMAKE_DIST =                                    \
  tests/cmake/test.c                             \
  tests/cmake/test.sh
 
-VC_DIST = projects/README.md                           \
- projects/checksrc.bat                                 \
- projects/generate.bat
+VC_DIST = projects/README.md projects/generate.bat
 
 WINBUILD_DIST = winbuild/README.md \
  winbuild/MakefileBuild.vc winbuild/Makefile.vc winbuild/makedebug.bat