build(vim-patch): ':vim9' is n/a

1. Vim9 error messages, ex commands, are N/A.
2. ":scriptversion" is N/A:
3. Most `#.*define.*ex_ni$` are N/A
   because `FEAT_` compile guards are N/A.

----

Target patch: v8.2.2238

Actual patch list:

```
vim-patch:8.2.4240: error for using flatten() in Vim9 script is unclear
vim-patch:9.0.0170: various minor code formatting issues
vim-patch:9.1.0356: MS-Windows: --remote may change working directory
vim-patch:9.2.0251: Link error when building without channel feature
vim-patch:9.2.0714: Coverity warns for NULL deref
vim-patch:9.2.0818: tests: client-server test fails without X11 server
vim-patch:9.2.0868: GTK: Window Manager hint prevents giving focus to dialog
```

----

Ignore diff blanklines via regex ("-I"), not "--ignore-blank-lines".
Almost useless.
I tried with/without "--word-diff=porcelain", "--word-diff-regex",
and diff algorithms like `--histogram`.

scripts/vim-patch.sh

@@ -942,11 +942,25 @@ is_na_patch() {
         fi
         ;;
       *.h)
-        HUNKS=$(git -C "${VIM_SOURCE_DIR}" diff-tree --no-commit-id -r -b -U0 '-I^#\s*(else|endif)' '-I^#\s*(ifdef|if.*defined\().*FEAT_' "$patch" -- "${file}")
+        HUNKS=$(git -C "${VIM_SOURCE_DIR}" diff-tree --no-commit-id -r -b -U0 \
+          '-I^\s+$' \
+          '-I^#\s*(ifdef|if.*defined\().*FEAT_' \
+          '-I^#\s*(else|endif)' \
+          '-I^EXTERN char e_.*vim9' \
+          '-I^\s*INIT\(= .+"E[0-9]+: .*[vV]im9' \
+          "$patch" -- "$file")
         test -n "${HUNKS}" && return 1
         ;;
       *.c)
-        HUNKS=$(git -C "${VIM_SOURCE_DIR}" diff-tree --no-commit-id -r -b -U0 '-I^#\s*(else|endif)' '-I^#\s*(ifdef|if.*defined\().*FEAT_' "$patch" -- "$file" | grep -P '^@@ .* @@')
+        HUNKS=$(git -C "${VIM_SOURCE_DIR}" diff-tree --no-commit-id -r -b -U0 \
+          '-I^\s+$' \
+          '-I^#\s*(ifdef|if.*defined\().*FEAT_' \
+          '-I^#\s*(else|endif)' \
+          '-I#\s*define.*ex_ni$' \
+          '-I[_.>]sc_version = ' \
+          '-I[_.>]uf_script_ctx_version = ' \
+          "$patch" -- "${file}" |
+          grep '^@@ .* @@')
         if test -n "$HUNKS"; then
           HUNK_NUM_FINAL=$(echo "$HUNKS" | sed 's/^@@ .* @@ \?//' | grep -cv -f "$NA_HUNKS_C")
           test "$HUNK_NUM_FINAL" -ne 0 && return 1

scripts/vim_na_hunks_vim.txt

@@ -1,3 +1,4 @@
+^:vim9.\+ .\+\*:vim9.\+\*
 ^balloon_[a-zA-Z0-9_]\+(.\+balloon_[a-zA-Z0-9_]\+(
 ^cscope_connection(.\+cscope_connection(
 ^js_decode(.\+js_decode(
@@ -87,6 +88,8 @@
 \*:shell\*
 \*:smile\*
 \*:version\*
+\*E984\*
+\*E999\*
 \*HelpToc-mappings\*
 \*SafeStateAgain\*
 \*SigUSR1\*