[at-spi2-core] Include strings.h for strcasecmp

[Mike Gorse <mgorse src gnome org>]

commit 90315b85e0fd8fcf59a51cb64ad981e8f54c5295
Author: Mike Gorse <mgorse alum wpi edu>
Date:   Sun Mar 3 17:53:15 2019 -0600

    Include strings.h for strcasecmp
    
    Fixes https://gitlab.gnome.org/GNOME/at-spi2-core/issues/5

 atspi/atspi-event-listener.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/atspi/atspi-event-listener.c b/atspi/atspi-event-listener.c
index 6a3fe6b..ae4a7b4 100644
--- a/atspi/atspi-event-listener.c
+++ b/atspi/atspi-event-listener.c
@@ -25,6 +25,7 @@
 #include "atspi-private.h"
 #include "atspi-accessible-private.h"
 #include <string.h>
+#include <strings.h>
 #include <ctype.h>
 
 typedef struct