tidy-up: miscellaneous

- avoid "will" in builds scripts, scripts folder, curl_easy_ssls_export.md,
  and few other files.
- badwords: add "initialise", "nul terminated", "thread safety" and
  variations.
- prefer "null-terminat", where missing (two places).
- fix "null-terminat*" missing dash.
- hostip: merge two `#if` blocks.
- tool_doswin: fix comment
  Spotted by GitHub Code Quality
  Follow-up to 9a2663322c #17572
- fix stray spaces and newlines.

Closes #21638

tests/testutil.pm

@@ -71,7 +71,7 @@ my @logmessages;  # array holding logged messages
 #
 # logmsg must only be called by one of the runner_* entry points and functions
 # called by them, or else logs risk being lost, since those are the only
-# functions that know about and will return buffered logs.
+# functions that know about and return buffered logs.
 sub logmsg {
     if(!scalar(@_)) {
         return;