tidy-up: .gitignore lines mostly

- `.gitignore`: delete, dedupe and move rules upwards.
  Ref: 6389ba87b8 #13311
- `.gitignore`: fix generated test sources.
  Follow-up to 71cf0d1fca #14772
- `.gitignore`: replace exe listings with a wildcard.
- lib: move `setup-*.h` from `EXTRA_DIST` to `CURL_HFILES`.
- `makedebug.bat`: uppercase an argument to match docs.
- GHA/non-native: delete stray env.
  Follow-up to 12a6de2f66 #16043
- sort source lists.

Closes #16093

docs/examples/.gitignore

@@ -2,120 +2,4 @@
 #
 # SPDX-License-Identifier: curl
 
-10-at-a-time
-address-scope
-altsvc
-anyauthput
-block_ip
-certinfo
-chkspeed
-connect-to
-cookie_interface
-debug
-default-scheme
-externalsocket
-fileupload
-fopen
-ftp-wildcard
-ftpget
-ftpgetinfo
-ftpgetresp
-ftpsget
-ftpupload
-ftpuploadfrommem
-ftpuploadresume
-getinfo
-getinmemory
-getredirect
-getreferrer
-headerapi
-hsts-preload
-http-options
-http-post
-http2-download
-http2-pushinmemory
-http2-serverpush
-http2-upload
-http3
-http3-present
-httpcustomheader
-httpput
-httpput-postfields
-https
-imap-append
-imap-authzid
-imap-copy
-imap-create
-imap-delete
-imap-examine
-imap-fetch
-imap-list
-imap-lsub
-imap-multi
-imap-noop
-imap-search
-imap-ssl
-imap-store
-imap-tls
-interface
-ipv6
-keepalive
-localport
-maxconnects
-multi-app
-multi-debugcallback
-multi-double
-multi-formadd
-multi-legacy
-multi-poll
-multi-post
-multi-single
-netrc
-new-gitignore
-parseurl
-persistent
-pop3-authzid
-pop3-dele
-pop3-list
-pop3-multi
-pop3-noop
-pop3-retr
-pop3-ssl
-pop3-stat
-pop3-tls
-pop3-top
-pop3-uidl
-post-callback
-postinmemory
-postit2
-postit2-formadd
-progressfunc
-protofeats
-range
-resolve
-rtsp
-rtsp-options
-sendrecv
-sepheaders
-sftpget
-sftpuploadresume
-shared-connection-cache
-simple
-simplepost
-simplessl
-smtp-authzid
-smtp-expn
-smtp-mail
-smtp-mime
-smtp-multi
-smtp-ssl
-smtp-tls
-smtp-vrfy
-sslbackend
-unixsocket
-url2file
-urlapi
-usercertinmem
-websocket
-websocket-cb
-xmlstream
+/[0-9a-z_-]+

docs/examples/Makefile.inc

@@ -82,7 +82,7 @@ check_PROGRAMS = \
   ipv6 \
   keepalive \
   localport \
-  maxconnects  \
+  maxconnects \
   multi-app \
   multi-debugcallback \
   multi-double \