Update bazel WORKSPACE and BUILD files to work better on Windows. (#581)

Note, bazel only supports MSVC on Windows, and not MinGW, so
linking against shlwapi.lib only needs to follow MSVC conventions.

git_repository() did not work in local testing, so is swapped for
http_archive(). The latter is also documented as the preferred way
to depend on an external library in bazel.

BUILD.bazel

@@ -16,7 +16,7 @@ cc_library(
     ]),
     hdrs = ["include/benchmark/benchmark.h"],
     linkopts = select({
-        ":windows": [],
+        ":windows": ["-DEFAULTLIB:shlwapi.lib"],
         "//conditions:default": ["-pthread"],
     }),
     strip_include_prefix = "include",

README.md

@@ -933,7 +933,7 @@ sudo cpupower frequency-set --governor powersave
 
 # Known Issues
 
-### Windows
+### Windows with CMake
 
 * Users must manually link `shlwapi.lib`. Failure to do so may result
 in unresolved symbols.

WORKSPACE

@@ -1,9 +1,7 @@
 workspace(name = "com_github_google_benchmark")
 
-load("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")
-
-git_repository(
+http_archive(
      name = "com_google_googletest",
-    commit = "3f0cf6b62ad1eb50d8736538363d3580dd640c3e",  # HEAD
-    remote = "https://github.com/google/googletest",
+     urls = ["https://github.com/google/googletest/archive/3f0cf6b62ad1eb50d8736538363d3580dd640c3e.zip"],
+     strip_prefix = "googletest-3f0cf6b62ad1eb50d8736538363d3580dd640c3e",
 )