boot_loader_openfirmware: Refactor Jamfile

The frame buffer will need more generic sources than just the text menu.
Adapted from bios_ia32 platform.

Part of ticket #6105.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@38301 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/system/boot/platform/openfirmware/Jamfile

@@ -2,6 +2,10 @@ SubDir HAIKU_TOP src system boot platform openfirmware ;
 
 SubDirC++Flags -D_BOOT_MODE -fno-rtti ;
 
+local genericPlatformSources =
+	text_menu.cpp
+;
+
 KernelMergeObject boot_platform_openfirmware.o :
 	console.cpp
 	debug.cpp
@@ -19,13 +23,12 @@ KernelMergeObject boot_platform_openfirmware.o :
 	openfirmware.cpp
 	openfirmware_devices.cpp
 
-	# generic
-	text_menu.cpp
+	$(genericPlatformSources)
 	:
 	: boot_platform_openfirmware_$(TARGET_ARCH).a
 ;
 
-SEARCH on [ FGristFiles text_menu.cpp ]
+SEARCH on [ FGristFiles $(genericPlatformSources) ]
 	= [ FDirName $(HAIKU_TOP) src system boot platform generic ] ;
 SEARCH on [ FGristFiles openfirmware.cpp openfirmware_devices.cpp ]
 	= [ FDirName $(HAIKU_TOP) src system kernel platform openfirmware ] ;