pkg/52164: [FIX] mail/claws-mail does not compile on macOS

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>Number:         52164
>Category:       pkg
>Synopsis:       [FIX] mail/claws-mail does not compile on macOS
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    pkg-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Apr 15 19:35:00 +0000 2017
>Originator:     Jonathan Schleifer
>Release:        HEAD
>Organization:
>Environment:
>Description:

>How-To-Repeat:

>Fix:
diff --git a/mail/claws-mail/Makefile b/mail/claws-mail/Makefile
index f11808945df..978391b06ee 100644
--- a/mail/claws-mail/Makefile
+++ b/mail/claws-mail/Makefile
@@ -77,7 +77,9 @@ PLIST_SRC+=   PLIST.shred
 .include "../../converters/libiconv/buildlink3.mk"
 .include "../../graphics/hicolor-icon-theme/buildlink3.mk"
 .include "../../x11/gtk2/buildlink3.mk"
+.if ${OPSYS} != "Darwin"
 .include "../../x11/startup-notification/buildlink3.mk"
+.endif
 .include "../../x11/libSM/buildlink3.mk"
 .include "../../sysutils/desktop-file-utils/desktopdb.mk"
 .include "../../mk/bdb.buildlink3.mk"