--- src/af/ev/gtk/ev_UnixMouse.cpp.orig	2019-11-26 18:22:10.000000000 -0700
+++ src/af/ev/gtk/ev_UnixMouse.cpp	2021-03-24 20:43:12.000000000 -0700
@@ -31,6 +31,7 @@
 #include "ev_EditEventMapper.h"
 #include "xav_View.h"
 #include "gr_Graphics.h"
+#include <cmath>
 
 EV_UnixMouse::EV_UnixMouse(EV_EditEventMapper * pEEM)
 	: EV_Mouse(pEEM)
@@ -279,7 +280,7 @@
 		gdouble delta_x, delta_y;
 		delta_x = delta_y = 0.0;
 		if (gdk_event_get_scroll_deltas((GdkEvent*)e, &delta_x, &delta_y)) {
-			if (abs(delta_y) > abs(delta_x)) {
+			if (std::abs(delta_y) > std::abs(delta_x)) {
 				// vertical
 				dir = (delta_y > 0.0 ? GDK_SCROLL_DOWN : GDK_SCROLL_UP);
 			} else {