From 49a13b6eecb465f76266d9c47a2e6699a15e11c8 Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Wed, 20 Jul 2022 12:22:33 -0700
Subject: [PATCH] ircd::asio: Fix undefined-var-template error; enable
 -fpch-instantiate-templates.

---
 include/ircd/Makefile.am |  3 +--
 include/ircd/asio.h      | 14 ++++++++++++++
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/include/ircd/Makefile.am b/include/ircd/Makefile.am
index f9951c0b4..1540bd85f 100644
--- a/include/ircd/Makefile.am
+++ b/include/ircd/Makefile.am
@@ -7,8 +7,7 @@ AM_CXXFLAGS =#
 AM_CXXFLAGS += -x c++-header
 
 if CLANG11
-#TODO: XXX
-#AM_CXXFLAGS += -fpch-instantiate-templates
+AM_CXXFLAGS += -fpch-instantiate-templates
 endif
 
 if GCC
diff --git a/include/ircd/asio.h b/include/ircd/asio.h
index de81d8353..70ae7ed36 100644
--- a/include/ircd/asio.h
+++ b/include/ircd/asio.h
@@ -68,6 +68,20 @@ namespace boost
 #pragma GCC visibility pop
 #endif
 
+// Template-specializations for some functions we may redefine (interpose).
+// Declarations are needed for template instantiation in PCH and with LTO.
+#if defined(BOOST_ASIO_HAS_EPOLL)
+namespace boost::asio::detail
+{
+	using epoll_time_traits = asio::time_traits<posix_time::ptime>;
+
+	template<> std::size_t
+	epoll_reactor::cancel_timer(timer_queue<epoll_time_traits> &,
+	                            typename timer_queue<epoll_time_traits>::per_timer_data &,
+	                            std::size_t max);
+}
+#endif
+
 // Boost version dependent behavior for getting the io_service/io_context
 // abstract executor (recent versions) or the derived instance (old versions).
 namespace ircd::ios