[gnumeric] Fonts: avoid critical on font mapping

[Morten Welinder <mortenw src gnome org>]

commit 644e51c662fcc65043390a66df22703b3811a658
Author: Morten Welinder <terra gnome org>
Date:   Wed Oct 29 17:03:15 2014 -0400

    Fonts: avoid critical on font mapping

 ChangeLog   |    4 ++++
 src/style.c |    4 ++++
 2 files changed, 8 insertions(+), 0 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index d20925b..2d79910 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2014-10-28  Morten Welinder  <terra gnome org>
+
+       * src/style.c (find_font): Accept NULL font name.
+
 2014-10-27  Morten Welinder  <terra gnome org>
 
        * src/sheet.c (sheet_destroy_contents): Plug leak from fuzzed
diff --git a/src/style.c b/src/style.c
index d6f1c75..d768af0 100644
--- a/src/style.c
+++ b/src/style.c
@@ -80,6 +80,10 @@ static struct FontInfo *
 find_font (const char *font_name)
 {
        unsigned ui;
+
+       if (!font_name)
+               return NULL;
+
        for (ui = 0; ui < G_N_ELEMENTS (font_info); ui++) {
                if (!g_ascii_strcasecmp (font_info[ui].font_name, font_name))
                        return font_info + ui;