systemlibs: unbundle gast

tensorflow/workspace.bzl

@@ -324,6 +324,7 @@ def tf_workspace(path_prefix = "", tf_repo_name = ""):
         sha256 = "7068908321ecd2774f145193c4b34a11305bd104b4551b09273dfd1d6a374930",
         strip_prefix = "gast-0.2.0",
         build_file = clean_dep("//third_party:gast.BUILD"),
+        system_build_file = clean_dep("//third_party/systemlibs:gast.BUILD"),
     )
 
     tf_http_archive(

third_party/systemlibs/gast.BUILD

@@ -0,0 +1,12 @@
+licenses(["notice"])  # BSD 3-clause
+
+filegroup(
+    name = "PKG-INFO",
+    visibility = ["//visibility:public"],
+)
+
+py_library(
+    name = "gast",
+    srcs_version = "PY2AND3",
+    visibility = ["//visibility:public"],
+)

third_party/systemlibs/syslibs_configure.bzl

@@ -20,6 +20,7 @@ VALID_LIBS = [
     "cython",
     "double_conversion",
     "flatbuffers",
+    "gast_archive",
     "gif_archive",
     "grpc",
     "jemalloc",