Shellcheck everything (#10730)

* Shellcheck all shell scripts

* Implement Shellcheck's recommendations

* Shellcheck the distribution-specific files

* Include the distro scripts to trigger action

* Fix array usage (hopefully)

* Use single-quote string

TIL: single quote string in yaml treats everything as literal, but
double quote allows backslash escaping.

* Make all cmake commands use set+-x dance and fix macos getopts line

Make Claude happy

getopts has colon after a command which takes an argument

---------

Co-authored-by: SoftFever <softfeverever@gmail.com>

.github/workflows/shellcheck.yml

@@ -1,10 +1,14 @@
 on:
   push:
     paths:
-      - build_linux.sh
+      - '**.sh'
+      - 'scripts/linux.d/*'
   pull_request:
     paths:
-      - build_linux.sh
+      - '**.sh'
+      - 'scripts/linux.d/*'
+  schedule:
+      - cron: '55 7 * * *' # run once a day near midnight US Pacific time
   workflow_dispatch: # allows for manual dispatch
 
 name: "Shellcheck"
@@ -33,6 +37,8 @@ jobs:
           mv ~/shellcheck-"${INPUT_VERSION}"/shellcheck ~/shellcheck
 
       - uses: actions/checkout@v5
+        with:
+          fetch-depth: 1
 
-      - name: Shellcheck build_linux.sh
-        run: ~/shellcheck -e SC1090 build_linux.sh
+      - name: Shellcheck scripts
+        run: 'find . -not -name \*.md \( -path ./scripts/linux.d/\* -o -name \*.sh \) -print0 | xargs -0 ~/shellcheck'