Set CMAKE_INSTALL_LIBDIR in systemc build

systemc will build into lib64 in Rocky 8.

Change-Id: I1f948448b55d33976b0c658216368f7543f442f0
diff --git a/external/systemc.BUILD b/external/systemc.BUILD
index 9d62604..79f1579 100644
--- a/external/systemc.BUILD
+++ b/external/systemc.BUILD
@@ -13,6 +13,7 @@
         "CMAKE_POSITION_INDEPENDENT_CODE": "ON",
         "CMAKE_CXX_STANDARD": "17",
         "BUILD_SHARED_LIBS": "False",
+        "CMAKE_INSTALL_LIBDIR": "lib",
     },
     generate_args = [
         "-G Ninja",