sdl.bbclass: use ?= for APPNAME, APPIMAGE and APPDESKTOP defaults

diff --git a/classes/sdl.bbclass b/classes/sdl.bbclass
index 75f6ea8..d458a14 100644 (file)
--- a/classes/sdl.bbclass
+++ b/classes/sdl.bbclass
@@ -4,9 +4,9 @@
 
 DEPENDS += "virtual/libsdl libsdl-mixer libsdl-image"
 
-APPDESKTOP = "${PN}.desktop"
-APPNAME = "${PN}"
-APPIMAGE = "${PN}.png"
+APPDESKTOP ?= "${PN}.desktop"
+APPNAME ?= "${PN}"
+APPIMAGE ?= "${PN}.png"
 
 sdl_do_sdl_install() {
        install -d ${D}${palmtopdir}/bin