systemlibs: Unbundle BoringSSL dependency

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

tensorflow/workspace.bzl

@@ -531,6 +531,7 @@ def tf_workspace(path_prefix = "", tf_repo_name = ""):
         ],
         sha256 = "1188e29000013ed6517168600fc35a010d58c5d321846d6a6dfee74e4c788b45",
         strip_prefix = "boringssl-7f634429a04abc48e2eb041c81c5235816c96514",
+        system_build_file = clean_dep("//third_party/systemlibs:boringssl.BUILD"),
     )
 
     tf_http_archive(

third_party/systemlibs/boringssl.BUILD

@@ -0,0 +1,21 @@
+licenses(["notice"])
+
+filegroup(
+    name = "LICENSE",
+    visibility = ["//visibility:public"],
+)
+
+cc_library(
+    name = "crypto",
+    linkopts = ["-lcrypto"],
+    visibility = ["//visibility:public"],
+)
+
+cc_library(
+    name = "ssl",
+    linkopts = ["-lssl"],
+    visibility = ["//visibility:public"],
+    deps = [
+        ":crypto",
+    ],
+)

third_party/systemlibs/syslibs_configure.bzl

@@ -11,6 +11,7 @@ _TF_SYSTEM_LIBS = "TF_SYSTEM_LIBS"
 
 VALID_LIBS = [
     "astor_archive",
+    "boringssl",
     "com_googlesource_code_re2",
     "curl",
     "cython",