Add zstd library for git submodule

SpringMT · SpringMT · commit 299727a1f9e2 · 2017-02-04T00:55:01.000+09:00
diff --git a/.gitmodules b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "zstd"]
+	path = zstd
+	url = https://github.com/facebook/zstd.git
diff --git a/zstd b/zstd
@@ -0,0 +1 @@
+Subproject commit dc9931205a87fdf6b993b3e215139011d3ef9fee

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	`+[submodule "zstd"]`
	`2`	`+ path = zstd`
	`3`	`+ url = https://github.com/facebook/zstd.git`