diff --git a/ci/build.sh b/ci/build.sh
index c331e9ab4..22f4472d3 100755
--- a/ci/build.sh
+++ b/ci/build.sh
@@ -1,82 +1,92 @@
 #!/usr/bin/env bash
 set -o pipefail
 [[ "${DEBUG:-}" ]] && set -x
 
 declare -i failed
 failed=0
 
 # SC2046: Quote this to prevent word splitting.
 # SC1090: Can't follow non-constant source. Use a directive to specify location.
 # SC2039: In POSIX sh, 'local' is undefined.
 # SC2086: Double quote to prevent globbing and word splitting.
 # SC2154: var is referenced but not assigned.
 ignored_errors="SC1090,SC2039,SC2154"
 
 success() {
 	printf "\r\033[2K  [ \033[00;32mOK\033[0m ] Checking %s...\n" "$1"
 }
 
 warn() {
 	printf "\r\033[2K  [\033[0;33mWARNING\033[0m] Checking %s...\n" "$1"
 }
 
 fail() {
 	printf "\r\033[2K  [\033[0;31mFAIL\033[0m] Checking %s...\n" "$1"
 	failed=$((failed + 1))
 }
 
 check() {
 	local script="$1"
 
 	out="$(shellcheck -s sh -f gcc -x -e "$ignored_errors" "$script" 2>&1)"
 	rc=$?
 	if [ $rc -eq 0 ]; then
 		success "$script"
 	elif echo "$out" | grep -i 'error' >/dev/null; then
 		fail "$script"
 	else
 		warn "$script"
 	fi
 	echo "$out"
 }
 
 find_prunes() {
 	local prunes="! -path './.git/*'"
 	if [ -f .gitmodules ]; then
 		while read -r module; do
 			prunes="$prunes ! -path './$module/*'"
 		done < <(grep path .gitmodules | awk '{print $3}')
 	fi
 	echo "$prunes"
 }
 
 find_cmd() {
-	echo "find heartbeat -type f -and \( -perm /111 -or -name '*.sh' \) $(find_prunes)"
+	echo "find heartbeat -type f -and \( -perm /111 -or -name '*.sh' -or -name '*.c' -or -name '*.in' \) $(find_prunes)"
 }
 
 check_all_executables() {
 	echo "Checking executables and .sh files..."
 	while read -r script; do
 		file --mime "$script" | grep 'charset=binary' >/dev/null 2>&1 && continue
 		file --mime "$script" | grep 'text/x-python' >/dev/null 2>&1 && continue
+		file --mime "$script" | grep 'text/x-makefile' >/dev/null 2>&1 && continue
+
+		if grep -qE "\<action.*(timeout|interval|delay)=\\\?\"[0-9]+\\\?\"" "$script"; then
+			fail "$script: \"s\"-suffix missing in timeout, interval or delay"
+		fi
+
 		head=$(head -n1 "$script")
 		[[ "$head" =~ .*ruby.* ]] && continue
 		[[ "$head" =~ .*zsh.* ]] && continue
 		[[ "$head" =~ ^#compdef.* ]] && continue
 		[[ "$script" =~ ^.*\.c ]] && continue
 		[[ "$script" =~ ^.*\.orig ]] && continue
 		[[ "$script" =~ ^ldirectord.in ]] && continue
 		check "$script"
+
 	done < <(eval "$(find_cmd)")
 	if [ $failed -gt 0 ]; then
 		echo "ci/build.sh: $failed failure(s) detected."
 		exit 1
 	fi
 	exit 0
 }
 
-./autogen.sh
-./configure
-make check
-[ $? -eq 0 ] || failed=$((failed + 1))
+if [ "$1" != "check" ]; then
+	./autogen.sh
+	./configure
+	make check
+	[ $? -eq 0 ] || failed=$((failed + 1))
+fi
+
 check_all_executables