libbe_build: Compile with support for Zstd.

This way, the build package commands will be able to deal with
and create Zstd-compressed packages.

src/build/libbe/Jamfile

@@ -16,7 +16,7 @@ BuildPlatformSharedLibrary libbe_build.so :
 
 	libshared_build.a
 
-	z $(HOST_LIBSUPC++) $(HOST_LIBSTDC++)
+	z zstd $(HOST_LIBSUPC++) $(HOST_LIBSTDC++)
 ;
 
 SubInclude HAIKU_TOP src build libbe app ;

src/build/libbe/support/Jamfile

@@ -7,6 +7,8 @@ USES_BE_API on <libbe_build>support_kit.o = true ;
 
 SEARCH_SOURCE += [ FDirName $(HAIKU_TOP) src kits support ] ;
 
+SubDirC++Flags -DZSTD_ENABLED ;
+
 BuildPlatformMergeObjectPIC <libbe_build>support_kit.o :
 	Archivable.cpp
 	BlockCache.cpp
@@ -26,4 +28,5 @@ BuildPlatformMergeObjectPIC <libbe_build>support_kit.o :
 	StringList.cpp
 	Url.cpp
 	ZlibCompressionAlgorithm.cpp
+	ZstdCompressionAlgorithm.cpp
 ;