macOS fix: Work around empty (sub)expression error when using BSD grep

test/lint/lint-locale-dependence.sh

@@ -197,11 +197,11 @@ REGEXP_IGNORE_KNOWN_VIOLATIONS=$(join_array "|" "${KNOWN_VIOLATIONS[@]}")
 
 # Invoke "git grep" only once in order to minimize run-time
 REGEXP_LOCALE_DEPENDENT_FUNCTIONS=$(join_array "|" "${LOCALE_DEPENDENT_FUNCTIONS[@]}")
-GIT_GREP_OUTPUT=$(git grep -E "[^a-zA-Z0-9_\`'\"<>](${REGEXP_LOCALE_DEPENDENT_FUNCTIONS}(|_r|_s))[^a-zA-Z0-9_\`'\"<>]" -- "*.cpp" "*.h")
+GIT_GREP_OUTPUT=$(git grep -E "[^a-zA-Z0-9_\`'\"<>](${REGEXP_LOCALE_DEPENDENT_FUNCTIONS}(_r|_s)?)[^a-zA-Z0-9_\`'\"<>]" -- "*.cpp" "*.h")
 
 EXIT_CODE=0
 for LOCALE_DEPENDENT_FUNCTION in "${LOCALE_DEPENDENT_FUNCTIONS[@]}"; do
-    MATCHES=$(grep -E "[^a-zA-Z0-9_\`'\"<>]${LOCALE_DEPENDENT_FUNCTION}(|_r|_s)[^a-zA-Z0-9_\`'\"<>]" <<< "${GIT_GREP_OUTPUT}" | \
+    MATCHES=$(grep -E "[^a-zA-Z0-9_\`'\"<>]${LOCALE_DEPENDENT_FUNCTION}(_r|_s)?[^a-zA-Z0-9_\`'\"<>]" <<< "${GIT_GREP_OUTPUT}" | \
         grep -vE "\.(c|cpp|h):\s*(//|\*|/\*|\").*${LOCALE_DEPENDENT_FUNCTION}" | \
         grep -vE 'fprintf\(.*(stdout|stderr)')
     if [[ ${REGEXP_IGNORE_EXTERNAL_DEPENDENCIES} != "" ]]; then

test/lint/lint-shell-locale.sh

@@ -16,7 +16,7 @@ for SHELL_SCRIPT in $(git ls-files -- "*.sh" | grep -vE "src/(secp256k1|univalue
     if grep -q "# This script is intentionally locale dependent by not setting \"export LC_ALL=C\"" "${SHELL_SCRIPT}"; then
         continue
     fi
-    FIRST_NON_COMMENT_LINE=$(grep -vE '^(#.*|)$' "${SHELL_SCRIPT}" | head -1)
+    FIRST_NON_COMMENT_LINE=$(grep -vE '^(#.*)?$' "${SHELL_SCRIPT}" | head -1)
     if [[ ${FIRST_NON_COMMENT_LINE} != "export LC_ALL=C" && ${FIRST_NON_COMMENT_LINE} != "export LC_ALL=C.UTF-8" ]]; then
         echo "Missing \"export LC_ALL=C\" (to avoid locale dependence) as first non-comment non-empty line in ${SHELL_SCRIPT}"
         EXIT_CODE=1