patch 8.2.0320: no Haiku support

Problem:    No Haiku support.
Solution:   Add support for Haiku. (Emir Sari, closes #5605)
diff --git a/src/evalfunc.c b/src/evalfunc.c
index cad7a96..ff891ea 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -3264,6 +3264,9 @@
 #ifdef __BEOS__
 	"beos",
 #endif
+#ifdef __HAIKU__
+	"haiku",
+#endif
 #if defined(BSD) && !defined(MACOS_X)
 	"bsd",
 #endif
@@ -3450,6 +3453,9 @@
 #ifdef FEAT_GUI_GNOME
 	"gui_gnome",
 #endif
+#ifdef FEAT_GUI_HAIKU
+	"gui_haiku",
+#endif
 #ifdef FEAT_GUI_MAC
 	"gui_mac",
 #endif