marl: Add new source file for loongarch64.

Bug: swiftshader:178
Change-Id: If7e689f513cc2494b5efedea2d47b60a7099567a
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/68308
Reviewed-by: Chang Rebecca Swee Fun <rebecca.chang@starfivetech.com>
Presubmit-Ready: Alexis Hétu <sugoi@google.com>
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>
Commit-Queue: Alexis Hétu <sugoi@google.com>
Tested-by: Alexis Hétu <sugoi@google.com>
diff --git a/third_party/marl/BUILD.gn b/third_party/marl/BUILD.gn
index 0de8e83..d7cb142 100644
--- a/third_party/marl/BUILD.gn
+++ b/third_party/marl/BUILD.gn
@@ -86,6 +86,12 @@
         "src/osfiber_asm_rv64.h",
         "src/osfiber_asm_rv64.S",
       ]
+    } else if (current_cpu == "loong64") {
+      sources += [
+        "src/osfiber_loongarch64.c",
+        "src/osfiber_asm_loongarch64.h",
+        "src/osfiber_asm_loongarch64.S",
+      ]
     } else if (current_cpu == "x64") {
       sources += [
         "src/osfiber_x64.c",