Switch everything to platforms

This patch switches the codebase over from using the "cpu"
mechanism to using bazel platforms. See
https://docs.bazel.build/versions/master/platforms.html for some more
information.

Most of the substantial changes are in //tools. Instead of using
`cc_toolchain_suite` rules, we now use regular `toolchain` rules that
are registered in the WORKSPACE. That also means that bazel now uses
the target platform to select the compiler.

All --cpu=* arguments should now be --config=* arguments. For example,
`--cpu=roborio` should now be `--config=roborio`. The CI script and
all documentation has been updated to reflect that.

The remainder of the changes revolve around tagging all targets with
`target_compatible_with`.  The old mechanism allowed us to specify
repo-wide defaults. The new mechanism does not. That means every
target that didn't have any compatibility specified, now requires
compatibility with `@platforms//os:linux`.

I used buildozer for the vast majority of `target_compatible_with`
changes. buildozer automatically buildifies any BUILD files it
touches. That means this patch also contains a few non-functional
changes that I was too lazy to remove.

Change-Id: I66d6e6ad9161520ee397597cdb492585820a3acd
diff --git a/y2016/vision/BUILD b/y2016/vision/BUILD
index 072b6ca..2a8031d 100644
--- a/y2016/vision/BUILD
+++ b/y2016/vision/BUILD
@@ -1,6 +1,7 @@
 load("@com_google_protobuf//:protobuf.bzl", "cc_proto_library")
 load("@com_github_google_flatbuffers//:build_defs.bzl", "flatbuffer_cc_library")
 load("//tools/build_rules:gtk_dependent.bzl", "gtk_dependent_cc_binary", "gtk_dependent_cc_library")
+load("//tools:platforms.bzl", "platforms")
 
 flatbuffer_cc_library(
     name = "vision_fbs",
@@ -8,17 +9,20 @@
         "vision.fbs",
     ],
     gen_reflections = 1,
+    target_compatible_with = ["@platforms//os:linux"],
     visibility = ["//visibility:public"],
 )
 
 cc_proto_library(
     name = "vision_data",
     srcs = ["vision_data.proto"],
+    target_compatible_with = ["@platforms//os:linux"],
 )
 
 cc_proto_library(
     name = "calibration",
     srcs = ["calibration.proto"],
+    target_compatible_with = ["@platforms//os:linux"],
 )
 
 _calibration_values_embedded_before = """
@@ -60,6 +64,7 @@
         "cat $(location :calibration.pb) | sed 's/\"/\\\\\"/g ; s/^/\"/g ; s/$$/\\\\n\"/g' >> $@",
         "echo '%s' >> $@" % _calibration_values_embedded_after,
     ]),
+    target_compatible_with = ["@platforms//os:linux"],
 )
 
 cc_library(
@@ -71,6 +76,7 @@
     hdrs = [
         "stereo_geometry.h",
     ],
+    target_compatible_with = ["@platforms//os:linux"],
     deps = [
         ":calibration",
         "//aos/logging",
@@ -81,10 +87,10 @@
 cc_binary(
     name = "target_sender",
     srcs = ["target_sender.cc"],
-    restricted_to = [
-        "//tools:k8",
-        "//tools:armhf-debian",
-    ],
+    target_compatible_with = platforms.any_of([
+        "@platforms//cpu:x86_64",
+        "//tools/platforms/hardware:raspberry_pi",
+    ]),
     deps = [
         ":calibration",
         ":stereo_geometry",
@@ -106,10 +112,10 @@
     name = "blob_filters",
     srcs = ["blob_filters.cc"],
     hdrs = ["blob_filters.h"],
-    restricted_to = [
-        "//tools:k8",
-        "//tools:armhf-debian",
-    ],
+    target_compatible_with = platforms.any_of([
+        "@platforms//cpu:x86_64",
+        "//tools/platforms/hardware:raspberry_pi",
+    ]),
     visibility = ["//visibility:public"],
     deps = [
         "//aos/vision/blob:codec",
@@ -127,6 +133,7 @@
     srcs = [
         "target_receiver.cc",
     ],
+    target_compatible_with = ["@platforms//os:linux"],
     visibility = ["//visibility:public"],
     deps = [
         ":stereo_geometry",
@@ -146,10 +153,10 @@
 gtk_dependent_cc_binary(
     name = "debug_receiver",
     srcs = ["debug_receiver.cc"],
-    restricted_to = [
-        "//tools:k8",
-        "//tools:armhf-debian",
-    ],
+    target_compatible_with = platforms.any_of([
+        "@platforms//cpu:x86_64",
+        "//tools/platforms/hardware:raspberry_pi",
+    ]),
     visibility = ["//visibility:public"],
     deps = [
         ":blob_filters",
diff --git a/y2016/vision/tools/BUILD b/y2016/vision/tools/BUILD
index edbfca5..62ed6b4 100644
--- a/y2016/vision/tools/BUILD
+++ b/y2016/vision/tools/BUILD
@@ -1,12 +1,13 @@
 load("//tools/build_rules:gtk_dependent.bzl", "gtk_dependent_cc_binary", "gtk_dependent_cc_library")
+load("//tools:platforms.bzl", "platforms")
 
 gtk_dependent_cc_binary(
     name = "blob_stream_replay",
     srcs = ["blob_stream_replay.cc"],
-    restricted_to = [
-        "//tools:k8",
-        "//tools:armhf-debian",
-    ],
+    target_compatible_with = platforms.any_of([
+        "@platforms//cpu:x86_64",
+        "//tools/platforms/hardware:raspberry_pi",
+    ]),
     deps = [
         "//aos/vision/blob:range_image",
         "//aos/vision/blob:stream_view",