Merge pull request #5 from hcindyl:build-antlr4

PiperOrigin-RevId: 526120720
Change-Id: I3c72bd6192a8fa3c91288b46d91f7999d08816cc

external/BUILD.antlr4

diff --git a/external/BUILD.antlr4 b/external/BUILD.antlr4
index 994787d..920a68d 100644
--- a/external/BUILD.antlr4
+++ b/external/BUILD.antlr4
@@ -27,6 +27,9 @@
     cache_entries = {
         "CMAKE_CXX_FLAGS": "-std=c++17",
     },
+    generate_args = [
+        "-G Ninja",
+    ],
     lib_source = ":all_srcs",
     tags = ["requires-network"],
     out_static_libs = ["libantlr4-runtime.a"],