merge bitcoin#20359: Various config.site.in improvements and linting

depends/config.site.in

@@ -1,4 +1,14 @@
-depends_prefix="`dirname ${ac_site_file}`/.."
+# shellcheck shell=sh disable=SC2034 # Many variables set will be used in
+                                     # ./configure but shellcheck doesn't know
+                                     # that, hence: disable=SC2034
+
+true  # Dummy command because shellcheck treats all directives before first
+      # command as file-wide, and we only want to disable for one line.
+      #
+      # See: https://github.com/koalaman/shellcheck/wiki/Directive
+
+# shellcheck disable=SC2154
+depends_prefix="$(cd "$(dirname ${ac_site_file})/.." && pwd)"
 
 cross_compiling=maybe
 host_alias=@HOST@
@@ -60,7 +70,7 @@ if test x@host_os@ = xmingw32; then
 fi
 
 PATH=$depends_prefix/native/bin:$PATH
-PKG_CONFIG="`which pkg-config` --static"
+PKG_CONFIG="$(which pkg-config) --static"
 
 # These two need to remain exported because pkg-config does not see them
 # otherwise. That means they must be unexported at the end of configure.ac to
@@ -78,7 +88,7 @@ fi
 if test -n "@CXX@" -a -z "${CXX}"; then
   CXX="@CXX@"
 fi
-PYTHONPATH=$depends_prefix/native/lib/python3/dist-packages:$PYTHONPATH
+PYTHONPATH="${depends_prefix}/native/lib/python3/dist-packages${PYTHONPATH:+${PATH_SEPARATOR}}${PYTHONPATH}"
 
 if test -n "@AR@"; then
   AR=@AR@

test/lint/lint-shell.sh

@@ -57,7 +57,8 @@ if ! command -v gawk > /dev/null; then
 fi
 
 EXCLUDE="--exclude=$(IFS=','; echo "${disabled[*]}")"
-if ! shellcheck "$EXCLUDE" $(git ls-files -- '*.sh' | grep -vE 'src/(leveldb|secp256k1|univalue)/'); then
+SOURCED_FILES=$(git ls-files | xargs gawk '/^# shellcheck shell=/ {print FILENAME} {nextfile}')  # Check shellcheck directive used for sourced files
+if ! shellcheck "$EXCLUDE" $SOURCED_FILES $(git ls-files -- '*.sh' | grep -vE 'src/(leveldb|secp256k1|univalue)/'); then
     EXIT_CODE=1
 fi