systemlibs: unbundle absl_py dependency

absl_py has rules in many dirs so this uses system_link_files to put
files in the right place.

Signed-off-by: Jason Zaman <jason@perfinion.com>

tensorflow/workspace.bzl

@@ -341,6 +341,11 @@ def tf_workspace(path_prefix = "", tf_repo_name = ""):
         ],
         sha256 = "95160f778a62c7a60ddeadc7bf2d83f85a23a27359814aca12cf949e896fa82c",
         strip_prefix = "abseil-py-pypi-v0.2.2",
+        system_build_file = clean_dep("//third_party/systemlibs:absl_py.BUILD"),
+        system_link_files = {
+            "//third_party/systemlibs:absl_py.absl.flags.BUILD": "absl/flags/BUILD",
+            "//third_party/systemlibs:absl_py.absl.testing.BUILD": "absl/testing/BUILD",
+        },
     )
 
     tf_http_archive(

third_party/systemlibs/absl_py.BUILD

@@ -0,0 +1 @@
+licenses(["notice"])  # Apache 2.0

third_party/systemlibs/absl_py.absl.flags.BUILD

@@ -0,0 +1,11 @@
+licenses(["notice"])  # Apache 2.0
+
+package(default_visibility = ["//visibility:public"])
+
+filegroup(
+    name = "LICENSE",
+)
+
+py_library(
+    name = "flags",
+)

third_party/systemlibs/absl_py.absl.testing.BUILD

@@ -0,0 +1,7 @@
+licenses(["notice"])  # Apache 2.0
+
+py_library(
+    name = "parameterized",
+    testonly = 1,
+    visibility = ["//visibility:public"],
+)

third_party/systemlibs/syslibs_configure.bzl

@@ -10,6 +10,7 @@
 _TF_SYSTEM_LIBS = "TF_SYSTEM_LIBS"
 
 VALID_LIBS = [
+    "absl_py",
     "astor_archive",
     "boringssl",
     "com_googlesource_code_re2",