set up GPU environment (#294)

* BLD: compile gpu kernel for image_projective_transform_op_gpu

* BUG: minor fix

* TST: use gpu

* BLD: fix code style

* CLN: move gpu dir to external dir

* CLN: configure ABI flag

* CLN: leave TODO in configure.sh

* CLN: create cuda_libs target

* CLN: fork use_gpu

* CLN: fix code style

* CLN: remove -c opt and use CUDA_HOME

* CLN: rename external => build_deps

* CLN: add requirements_gpu.txt

* TST: disable failed test cases on GPU

* CLN: tracked by compile issue

Author: facaiy

WORKSPACE

@@ -1,5 +1,7 @@
 load("//tf_dependency:tf_configure.bzl", "tf_configure")
+load("//build_deps/gpu:cuda_configure.bzl", "cuda_configure")
 
 tf_configure(
     name = "local_config_tf",
 )
+cuda_configure(name = "local_config_cuda")

build_deps/gpu/BUILD

@@ -0,0 +1,96 @@
+licenses(["restricted"])
+
+package(default_visibility = ["//visibility:public"])
+
+toolchain(
+    name = "toolchain-linux-x86_64",
+    exec_compatible_with = [
+        "@bazel_tools//platforms:linux",
+        "@bazel_tools//platforms:x86_64",
+    ],
+    target_compatible_with = [
+        "@bazel_tools//platforms:linux",
+        "@bazel_tools//platforms:x86_64",
+    ],
+    toolchain = ":cc-compiler-local",
+    toolchain_type = "@bazel_tools//tools/cpp:toolchain_type",
+)
+
+cc_toolchain_suite(
+    name = "toolchain",
+    toolchains = {
+        "local|compiler": ":cc-compiler-local",
+        "darwin|compiler": ":cc-compiler-darwin",
+        "x64_windows|msvc-cl": ":cc-compiler-windows",
+        "x64_windows": ":cc-compiler-windows",
+        "arm": ":cc-compiler-local",
+        "k8": ":cc-compiler-local",
+        "piii": ":cc-compiler-local",
+        "ppc": ":cc-compiler-local",
+        "darwin": ":cc-compiler-darwin",
+    },
+)
+
+cc_toolchain(
+    name = "cc-compiler-local",
+    all_files = "%{linker_files}",
+    compiler_files = ":empty",
+    cpu = "local",
+    dwp_files = ":empty",
+    dynamic_runtime_libs = [":empty"],
+    linker_files = "%{linker_files}",
+    objcopy_files = ":empty",
+    static_runtime_libs = [":empty"],
+    strip_files = ":empty",
+    # To support linker flags that need to go to the start of command line
+    # we need the toolchain to support parameter files. Parameter files are
+    # last on the command line and contain all shared libraries to link, so all
+    # regular options will be left of them.
+    supports_param_files = 1,
+    toolchain_identifier = "local_linux",
+)
+
+cc_toolchain(
+    name = "cc-compiler-darwin",
+    all_files = "%{linker_files}",
+    compiler_files = ":empty",
+    cpu = "darwin",
+    dwp_files = ":empty",
+    dynamic_runtime_libs = [":empty"],
+    linker_files = "%{linker_files}",
+    objcopy_files = ":empty",
+    static_runtime_libs = [":empty"],
+    strip_files = ":empty",
+    supports_param_files = 0,
+    toolchain_identifier = "local_darwin",
+)
+
+cc_toolchain(
+    name = "cc-compiler-windows",
+    all_files = "%{win_linker_files}",
+    compiler_files = ":empty",
+    cpu = "x64_windows",
+    dwp_files = ":empty",
+    dynamic_runtime_libs = [":empty"],
+    linker_files = "%{win_linker_files}",
+    objcopy_files = ":empty",
+    static_runtime_libs = [":empty"],
+    strip_files = ":empty",
+    supports_param_files = 1,
+    toolchain_identifier = "local_windows",
+)
+
+filegroup(
+    name = "empty",
+    srcs = [],
+)
+
+filegroup(
+    name = "crosstool_wrapper_driver_is_not_gcc",
+    srcs = ["clang/bin/crosstool_wrapper_driver_is_not_gcc"],
+)
+
+filegroup(
+    name = "windows_msvc_wrapper_files",
+    srcs = glob(["windows/msvc_*"]),
+)