U-Boot: compile and link to libfdt

* For the sam460ex and likely some ARM boards we will try to boot
using the passed FDT, as it's the recommended method now.

(cherry picked from my sam460ex branch)

src/system/boot/platform/u-boot/Jamfile

@@ -22,6 +22,17 @@ UsePrivateHeaders [ FDirName kernel arch $(TARGET_ARCH) board $(TARGET_BOOT_BOAR
 	SubDirC++Flags $(defines) -fno-rtti -g3 -O0 ;
 }
 
+UseLibraryHeaders [ FDirName libfdt ] ;
+
+local libFDTSources =
+	fdt.c
+	fdt_ro.c
+	fdt_rw.c
+	fdt_strerror.c
+	fdt_sw.c
+	fdt_wip.c
+;
+
 # we fake NetBSD since we don't have an OS ID yet for uimage,
 # and we also fake a netbsd loader anyway.
 local uImageFakeOS = "netbsd" ;
@@ -41,6 +52,7 @@ KernelMergeObject boot_platform_u-boot_common.o :
 	uimage.cpp
 	video.cpp
 	$(genericPlatformSources)
+	$(libFDTSources)
 
 
 	: -fno-pic
@@ -234,6 +246,9 @@ Depends haiku-mmc-image : haiku-$(HAIKU_BOOT_BOARD).mmc ;
 SEARCH on [ FGristFiles $(genericPlatformSources) ]
 	= [ FDirName $(HAIKU_TOP) src system boot platform generic ] ;
 
+SEARCH on [ FGristFiles $(libFDTSources) ]
+	= [ FDirName $(HAIKU_TOP) src libs libfdt ] ;
+
 # Tell the build system to where stage1.bin can be found, so it can be used
 # elsewhere.
 SEARCH on stage1.bin = $(SUBDIR) ;