[goffice] go_complex_angle_pi: pick proper branch cut.

[Morten Welinder <mortenw src gnome org>]

commit 9d65a48c94a04503d574c067758297696f0c1a34
Author: Morten Welinder <terra gnome org>
Date:   Mon Dec 16 21:55:36 2013 -0500

    go_complex_angle_pi: pick proper branch cut.

 goffice/math/go-complex.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/goffice/math/go-complex.c b/goffice/math/go-complex.c
index 7822e86..b1cedf7 100644
--- a/goffice/math/go-complex.c
+++ b/goffice/math/go-complex.c
@@ -481,7 +481,7 @@ DOUBLE SUFFIX(go_complex_angle) (COMPLEX const *src)
 DOUBLE SUFFIX(go_complex_angle_pi) (COMPLEX const *src)
 {
        if (src->im == 0)
-               return (src->re >= 0 ? 0 : -1);
+               return (src->re >= 0 ? 0 : +1);
 
        if (src->re == 0)
                return (src->im >= 0 ? 0.5 : -0.5);