[gimp/gimp-2-10] Issue #2635 - Segfault when using measuring tool

[Ell <ell src gnome org>]

commit a2c20b15392d456b36afdc9074d1176f02403b29
Author: Ell <ell_se yahoo com>
Date:   Sat Dec 8 05:59:05 2018 -0500

    Issue #2635 - Segfault when using measuring tool
    
    In gimp_tool_compass_update_angle(), use fuzzy comparisson when
    determining whether to update the angle properties, to avoid
    infinite recursion due to floating-point inaccuracies.  In
    partcicular, on x86, when using the x87 FPU rather than SSE, the
    floating-point registers are 80-bit, while the properties are
    stored as 64-bit, which can create small discrepancies between the
    calculated angles and the stored values.
    
    (cherry picked from commit ad831dbc6d4a0ac0ad05b0b17f94373605692d61)

 app/display/gimptoolcompass.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/app/display/gimptoolcompass.c b/app/display/gimptoolcompass.c
index 626195c148..28e7d43b54 100644
--- a/app/display/gimptoolcompass.c
+++ b/app/display/gimptoolcompass.c
@@ -1155,14 +1155,14 @@ gimp_tool_compass_update_angle (GimpToolCompass        *compass,
         }
     }
 
-  if (pixel_angle != private->pixel_angle)
+  if (fabs (pixel_angle - private->pixel_angle) > EPSILON)
     {
       private->pixel_angle = pixel_angle;
 
       g_object_notify (G_OBJECT (compass), "pixel-angle");
     }
 
-  if (unit_angle != private->unit_angle)
+  if (fabs (unit_angle - private->unit_angle) > EPSILON)
     {
       private->unit_angle = unit_angle;