Adds patch generated from mhillenibm's PR (see https://github.com/thjaeger/easystroke/pull/14)

Move-Stroke-save-and-load-into-header.patch

From 686b7778767f1f94cf9f6d5c2acd401d76bb3d4a Mon Sep 17 00:00:00 2001
From: Marius Hillenbrand <mhillen@linux.ibm.com>
Date: Tue, 14 Apr 2020 16:00:36 +0200
Subject: [PATCH] Move Stroke::save() and load() into header

The template member functions Stroke::save and Stroke::load get called
via the serialize() function generated by boost's macro
BOOST_SERIALIZATION_SPLIT_MEMBER() in gesture.h.  Since the definitions
of save()/load() are only available in gesture.cc, the compiler may
produce two versions of Stroke::serialize() -- one with save()/load()
inlined in gesture.o and one with calls to save()/load() in all other
referencing translation units. Since the compiler inlined Stroke::save()
and Stroke::load(), it will not export them in gesture.o (which is
legitimate, since the code only requests an export of
Stroke::serialize). As a result, some orders of object files can fail to
link, when the linker picks the version of Stroke::serialize() that
would call save()/load() (which are not available separately) instead of
the version with these functions inlined.

Avoid relying on this compiler- and optimization-level dependent
behavior by moving the definition of template member functions
Stroke::save() and Stroke::load() into gesture.h. As a side-effect, that
change unifies code style, since all other classes have their ::save()
and ::load() definitions in header files, too.

These link failures surfaced when building on s390x with -march=zEC12 or
later, and can be reproduced on x86_64 with gcc parameters
    --param max-inline-insns-auto=80 --param inline-min-speedup=2

Signed-off-by: Marius Hillenbrand <mhillen@linux.ibm.com>
---
 gesture.cc | 36 ------------------------------------
 gesture.h  | 37 +++++++++++++++++++++++++++++++++++--
 2 files changed, 35 insertions(+), 38 deletions(-)

diff --git a/gesture.cc b/gesture.cc
index 8531c08..f97bce3 100644
--- a/gesture.cc
+++ b/gesture.cc
@@ -14,7 +14,6 @@
  * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 #include "gesture.h"
-#include "prefdb.h"
 
 #include <boost/archive/text_oarchive.hpp>
 #include <boost/archive/text_iarchive.hpp>
@@ -35,41 +34,6 @@ RTriple create_triple(float x, float y, Time t) {
 	return e;
 }
 
-template<class Archive> void Stroke::save(Archive & ar, const unsigned int version) const {
-	std::vector<Point> ps;
-	for (unsigned int i = 0; i < size(); i++)
-		ps.push_back(points(i));
-	ar & ps;
-	ar & button;
-	ar & trigger;
-	ar & timeout;
-	ar & modifiers;
-}
-
-template<class Archive> void Stroke::load(Archive & ar, const unsigned int version) {
-	std::vector<Point> ps;
-	ar & ps;
-	if (ps.size()) {
-		stroke_t *s = stroke_alloc(ps.size());
-		for (std::vector<Point>::iterator i = ps.begin(); i != ps.end(); ++i)
-			stroke_add_point(s, i->x, i->y);
-		stroke_finish(s);
-		stroke.reset(s, &stroke_free);
-	}
-	if (version == 0) return;
-	ar & button;
-	if (version >= 2)
-		ar & trigger;
-	if (version < 4 && (!button || trigger == (int)prefs.button.get().button))
-		trigger = 0;
-	if (version < 3)
-		return;
-	ar & timeout;
-	if (version < 5)
-		return;
-	ar & modifiers;
-}
-
 Stroke::Stroke(PreStroke &ps, int trigger_, int button_, unsigned int modifiers_, bool timeout_) : trigger(trigger_), button(button_), modifiers(modifiers_), timeout(timeout_) {
 	if (ps.valid()) {
 		stroke_t *s = stroke_alloc(ps.size());
diff --git a/gesture.h b/gesture.h
index accecdf..1c31887 100644
--- a/gesture.h
+++ b/gesture.h
@@ -16,6 +16,7 @@
 #ifndef __GESTURE_H__
 #define __GESTURE_H__
 
+#include "prefdb.h"
 #include "stroke.h"
 #include <gdkmm.h>
 #include <vector>
@@ -83,8 +84,40 @@ private:
 	static Glib::RefPtr<Gdk::Pixbuf> pbEmpty;
 
 	BOOST_SERIALIZATION_SPLIT_MEMBER()
-	template<class Archive> void load(Archive & ar, const unsigned int version);
-	template<class Archive> void save(Archive & ar, const unsigned int version) const;
+	template<class Archive> void load(Archive & ar, const unsigned int version) {
+		std::vector<Point> ps;
+		ar & ps;
+		if (ps.size()) {
+			stroke_t *s = stroke_alloc(ps.size());
+			for (std::vector<Point>::iterator i = ps.begin(); i != ps.end(); ++i)
+				stroke_add_point(s, i->x, i->y);
+			stroke_finish(s);
+			stroke.reset(s, &stroke_free);
+		}
+		if (version == 0) return;
+		ar & button;
+		if (version >= 2)
+			ar & trigger;
+		if (version < 4 && (!button || trigger == (int)prefs.button.get().button))
+			trigger = 0;
+		if (version < 3)
+			return;
+		ar & timeout;
+		if (version < 5)
+			return;
+		ar & modifiers;
+
+	}
+	template<class Archive> void save(Archive & ar, const unsigned int version) const {
+		std::vector<Point> ps;
+		for (unsigned int i = 0; i < size(); i++)
+			ps.push_back(points(i));
+		ar & ps;
+		ar & button;
+		ar & trigger;
+		ar & timeout;
+		ar & modifiers;
+	}
 public:
 	int trigger;
 	int button;
-- 
2.27.0

PKGBUILD

# Maintainer:  AppleBloom <rat.o.drat@gmail.com>

_pkgname="easystroke"
pkgname="$_pkgname-git"
pkgver=0.6.0.r9.gf7c1614
pkgrel=3
pkgdesc="Gesture-recognition application for X11."
arch=("i686" "x86_64")
url="https://github.com/thjaeger/easystroke/wiki"
license=("custom")
depends=("gtkmm3" "boost-libs" "libxtst" "dbus-glib" "xorg-server")
makedepends=("boost" "xorgproto" "intltool" "gettext" "xorg-server-devel" "help2man" "git")
provides=("$_pkgname")
conflicts=("$_pkgname")
install="$_pkgname.install"
source=("git+https://github.com/thjaeger/easystroke.git"
        "sigc.patch"
        "dont-ignore-xshape-when-saving.patch"
        "add-toggle-option.patch"
        "abs.patch"
        "Move-Stroke-save-and-load-into-header.patch")
md5sums=("SKIP"
         "25fb4b21e36501276285caa788e1acd0"
         "b9cd799d59ec868371e8e6c538d43bf6"
         "39013c97c368735967a2f6897c96d614"
         "cf43fd18e370a37d9e780df97f1cbf92"
         "a89cda1b52869b448855f7ea796d0e7b")

pkgver() {
  cd "$_pkgname"
  git describe --long | sed "s/\([^-]*-g\)/r\1/;s/-/./g"
}

prepare() {
  cd "$_pkgname"
  for patch in ../*.patch
  do
    patch -i "$patch"
  done
}

build() {
  cd "$_pkgname"
  make
  make man
}

package() {
  cd "$_pkgname"
  make PREFIX="/usr" DESTDIR="$pkgdir" install
  install -Dm644 "$_pkgname.1" "$pkgdir/usr/share/man/man1/$_pkgname.1"
  install -Dm644 "LICENSE" "$pkgdir/usr/share/licenses/$_pkgname/LICENSE"
}

# vim:set ts=2 sw=2 et:

mhillenibm's PR made sense to me so I tried it out and it seems to work fine so far. Here's my modified PKGBUILD & patch in case you would like to add it to the easystroke-git AUR package. HTH