https://bugs.gentoo.org/917646
https://github.com/systemd-cron/systemd-cron/issues/141
https://github.com/systemd-cron/systemd-cron/commit/1662b899b206f00face30b9d4671551427262b07

From 1662b899b206f00face30b9d4671551427262b07 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=D0=BD=D0=B0=D0=B1?= <nabijaczleweli@nabijaczleweli.xyz>
Date: Tue, 21 Nov 2023 19:40:05 +0100
Subject: [PATCH] Add PCH= for broken compilers like #141

--- a/Makefile.in
+++ b/Makefile.in
@@ -1,6 +1,7 @@
 CFLAGS ?= -O2
 SHELLCHECK ?= shellcheck
 CRONTAB ?= crontab
+PCH ?= y
 
 version		:= @version@
 schedules		:= @schedules@
@@ -208,12 +209,12 @@ $(builddir)/include/%.hpp: $(srcdir)/include/%.hpp
 CXXVER := $(shell $(CXX) --version | { read -r l; echo "$$l"; })
 ifneq "$(findstring clang,$(CXXVER))" ""
 	# clang doesn't use PCHs automatically
-	PCH_ARG := -include-pch $(builddir)/include/libvoreutils.hpp.gch -Wno-gcc-compat
+	PCH_ARG := $(if $(PCH),-include-pch $(builddir)/include/libvoreutils.hpp.gch) -Wno-gcc-compat
 else
 	PCH_ARG :=
 endif
 
-common_headers := $(builddir)/include/configuration.hpp $(builddir)/include/libvoreutils.hpp.gch $(builddir)/include/util.hpp
+common_headers := $(builddir)/include/configuration.hpp $(builddir)/include/libvoreutils.hpp$(if $(PCH),.gch) $(builddir)/include/util.hpp
 CFLAGS += -Wall -Wextra -fno-exceptions -Wno-psabi
 $(builddir)/include/libvoreutils.hpp.gch : $(builddir)/include/libvoreutils.hpp
 	$(CXX) $(CFLAGS) $(CPPFLAGS) -std=c++20 -I $(builddir)/include            $< -o $@
--- a/README.md
+++ b/README.md
@@ -146,6 +146,8 @@ without the override, the jobs would run twice since native-timer detection woul
 If there is already a perfect 1:1 mapping between `/etc/cron.<freq>/<job>` and `/usr/lib/systemd/system/<job>.timer`,
 then it is not needed to add an entry to these tables.
 
+If your compiler's [PCH compilation is broken](https://github.com/systemd-cron/systemd-cron/issues/141), build with `make PCH=`.
+
 ### Caveat
 
 Your package should also run these extra commands before starting cron.target