Integrate LZ4 library, compress the ramdisk

lz4/lib/liblz4.pc.in

@@ -0,0 +1,15 @@
+#   LZ4 - Fast LZ compression algorithm
+#   Copyright (C) 2011-2020, Yann Collet.
+#   BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
+
+prefix=@PREFIX@
+libdir=@LIBDIR@
+includedir=@INCLUDEDIR@
+
+Name: lz4
+Description: extremely fast lossless compression algorithm library
+URL: http://www.lz4.org/
+License: BSD-2-Clause
+Version: @VERSION@
+Libs: -L${libdir} -llz4
+Cflags: -I${includedir}