Add LLVM 7.0 git submodule

Change-Id: I80b675f939f7eae95ad2fa637e77fc8d988bed3a
Reviewed-on: https://swiftshader-review.googlesource.com/20472
Tested-by: Logan Chien <loganchien@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
diff --git a/.gitmodules b/.gitmodules
index 5a4e85a..d80c7e2 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,3 +1,6 @@
 [submodule "third_party/googletest"]
 	path = third_party/googletest
 	url = https://github.com/google/googletest.git
+[submodule "third_party/llvm-7.0/llvm"]
+	path = third_party/llvm-7.0/llvm
+	url = https://git.llvm.org/git/llvm.git
diff --git a/third_party/llvm-7.0/llvm b/third_party/llvm-7.0/llvm
new file mode 160000
index 0000000..98aa61b
--- /dev/null
+++ b/third_party/llvm-7.0/llvm
@@ -0,0 +1 @@
+Subproject commit 98aa61ba49b54902a7afc27c9aa6c562646be76f