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/y2014/BUILD b/y2014/BUILD
index c77a019..4332a63 100644
--- a/y2014/BUILD
+++ b/y2014/BUILD
@@ -9,6 +9,7 @@
     hdrs = [
         "constants.h",
     ],
+    target_compatible_with = ["@platforms//os:linux"],
     visibility = ["//visibility:public"],
     deps = [
         "//aos/logging",
@@ -26,6 +27,7 @@
     srcs = [
         "joystick_reader.cc",
     ],
+    target_compatible_with = ["@platforms//os:linux"],
     deps = [
         ":constants",
         "//aos:init",
@@ -55,6 +57,7 @@
         "//y2014/control_loops/shooter:shooter",
         "//y2014/actors:binaries",
     ],
+    target_compatible_with = ["@platforms//os:linux"],
 )
 
 cc_binary(
@@ -62,6 +65,7 @@
     srcs = [
         "hot_goal_reader.cc",
     ],
+    target_compatible_with = ["@platforms//os:linux"],
     deps = [
         "//aos:byteorder",
         "//aos:init",
@@ -85,6 +89,7 @@
         "//y2014/control_loops/claw:claw_position_fbs",
         "//y2014/control_loops/claw:claw_status_fbs",
     ],
+    target_compatible_with = ["@platforms//os:linux"],
     visibility = ["//visibility:public"],
     deps = [
         "//aos/robot_state:config",
@@ -97,7 +102,7 @@
     srcs = [
         "wpilib_interface.cc",
     ],
-    restricted_to = ["//tools:roborio"],
+    target_compatible_with = ["//tools/platforms/hardware:roborio"],
     deps = [
         ":constants",
         "//aos:init",
@@ -139,5 +144,6 @@
 py_library(
     name = "python_init",
     srcs = ["__init__.py"],
+    target_compatible_with = ["@platforms//os:linux"],
     visibility = ["//visibility:public"],
 )
diff --git a/y2014/actors/BUILD b/y2014/actors/BUILD
index 82255ab..ab27aac 100644
--- a/y2014/actors/BUILD
+++ b/y2014/actors/BUILD
@@ -24,6 +24,7 @@
     hdrs = [
         "shoot_actor.h",
     ],
+    target_compatible_with = ["@platforms//os:linux"],
     visibility = ["//visibility:public"],
     deps = [
         "//aos/actions:action_lib",
@@ -41,6 +42,7 @@
     srcs = [
         "shoot_actor_main.cc",
     ],
+    target_compatible_with = ["@platforms//os:linux"],
     deps = [
         ":shoot_action_lib",
         "//aos:init",
@@ -56,6 +58,7 @@
     hdrs = [
         "autonomous_actor.h",
     ],
+    target_compatible_with = ["@platforms//os:linux"],
     deps = [
         "//aos/actions:action_lib",
         "//aos/events:event_loop",
@@ -78,6 +81,7 @@
     srcs = [
         "autonomous_actor_main.cc",
     ],
+    target_compatible_with = ["@platforms//os:linux"],
     deps = [
         ":autonomous_action_lib",
         "//aos:init",
diff --git a/y2014/control_loops/BUILD b/y2014/control_loops/BUILD
index 995a4c7..bbb88e0 100644
--- a/y2014/control_loops/BUILD
+++ b/y2014/control_loops/BUILD
@@ -1,6 +1,7 @@
 py_library(
     name = "python_init",
     srcs = ["__init__.py"],
+    target_compatible_with = ["@platforms//os:linux"],
     visibility = ["//visibility:public"],
     deps = ["//y2014:python_init"],
 )
diff --git a/y2014/control_loops/claw/BUILD b/y2014/control_loops/claw/BUILD
index 2ae59b0..f8865a5 100644
--- a/y2014/control_loops/claw/BUILD
+++ b/y2014/control_loops/claw/BUILD
@@ -8,6 +8,7 @@
         "claw_goal.fbs",
     ],
     gen_reflections = 1,
+    target_compatible_with = ["@platforms//os:linux"],
 )
 
 flatbuffer_cc_library(
@@ -19,6 +20,7 @@
     includes = [
         "//frc971/control_loops:control_loops_fbs_includes",
     ],
+    target_compatible_with = ["@platforms//os:linux"],
 )
 
 flatbuffer_cc_library(
@@ -27,6 +29,7 @@
         "claw_output.fbs",
     ],
     gen_reflections = 1,
+    target_compatible_with = ["@platforms//os:linux"],
 )
 
 flatbuffer_cc_library(
@@ -35,6 +38,7 @@
         "claw_status.fbs",
     ],
     gen_reflections = 1,
+    target_compatible_with = ["@platforms//os:linux"],
 )
 
 genrule(
@@ -44,6 +48,7 @@
         "claw_motor_plant.cc",
     ],
     cmd = "$(location //y2014/control_loops/python:claw) $(OUTS)",
+    target_compatible_with = ["@platforms//os:linux"],
     tools = [
         "//y2014/control_loops/python:claw",
     ],
@@ -63,6 +68,7 @@
     linkopts = [
         "-lm",
     ],
+    target_compatible_with = ["@platforms//os:linux"],
     deps = [
         ":claw_goal_fbs",
         ":claw_output_fbs",
@@ -84,6 +90,7 @@
         "claw_lib_test.cc",
     ],
     data = ["//y2014:config"],
+    target_compatible_with = ["@platforms//os:linux"],
     deps = [
         ":claw_goal_fbs",
         ":claw_lib",
@@ -102,6 +109,7 @@
     srcs = [
         "claw_main.cc",
     ],
+    target_compatible_with = ["@platforms//os:linux"],
     deps = [
         ":claw_lib",
         "//aos:init",
diff --git a/y2014/control_loops/drivetrain/BUILD b/y2014/control_loops/drivetrain/BUILD
index c458208..f331b37 100644
--- a/y2014/control_loops/drivetrain/BUILD
+++ b/y2014/control_loops/drivetrain/BUILD
@@ -9,6 +9,7 @@
         "kalman_drivetrain_motor_plant.cc",
     ],
     cmd = "$(location //y2014/control_loops/python:drivetrain) $(OUTS)",
+    target_compatible_with = ["@platforms//os:linux"],
     tools = [
         "//y2014/control_loops/python:drivetrain",
     ],
@@ -26,6 +27,7 @@
         "hybrid_velocity_drivetrain.cc",
     ],
     cmd = "$(location //y2014/control_loops/python:polydrivetrain) $(OUTS)",
+    target_compatible_with = ["@platforms//os:linux"],
     tools = [
         "//y2014/control_loops/python:polydrivetrain",
     ],
@@ -46,6 +48,7 @@
         "kalman_drivetrain_motor_plant.h",
         "polydrivetrain_dog_motor_plant.h",
     ],
+    target_compatible_with = ["@platforms//os:linux"],
     deps = [
         "//frc971/control_loops:hybrid_state_feedback_loop",
         "//frc971/control_loops:state_feedback_loop",
@@ -60,6 +63,7 @@
     hdrs = [
         "drivetrain_base.h",
     ],
+    target_compatible_with = ["@platforms//os:linux"],
     deps = [
         ":polydrivetrain_plants",
         "//frc971/control_loops/drivetrain:drivetrain_config",
@@ -72,6 +76,7 @@
     srcs = [
         "drivetrain_main.cc",
     ],
+    target_compatible_with = ["@platforms//os:linux"],
     deps = [
         ":drivetrain_base",
         "//aos:init",
diff --git a/y2014/control_loops/python/BUILD b/y2014/control_loops/python/BUILD
index cba8cea..60488b4 100644
--- a/y2014/control_loops/python/BUILD
+++ b/y2014/control_loops/python/BUILD
@@ -6,7 +6,7 @@
         "drivetrain.py",
     ],
     legacy_create_init = False,
-    restricted_to = ["//tools:k8"],
+    target_compatible_with = ["@platforms//os:linux"],
     deps = [
         ":python_init",
         "//external:python-gflags",
@@ -22,7 +22,7 @@
         "polydrivetrain.py",
     ],
     legacy_create_init = False,
-    restricted_to = ["//tools:k8"],
+    target_compatible_with = ["@platforms//os:linux"],
     deps = [
         ":python_init",
         "//external:python-gflags",
@@ -37,7 +37,7 @@
         "drivetrain.py",
         "polydrivetrain.py",
     ],
-    restricted_to = ["//tools:k8"],
+    target_compatible_with = ["@platforms//os:linux"],
     deps = [
         "//external:python-gflags",
         "//external:python-glog",
@@ -53,7 +53,7 @@
         "claw.py",
     ],
     legacy_create_init = False,
-    restricted_to = ["//tools:k8"],
+    target_compatible_with = ["@platforms//os:linux"],
     deps = [
         ":polydrivetrain_lib",
         ":python_init",
@@ -70,7 +70,7 @@
         "shooter.py",
     ],
     legacy_create_init = False,
-    restricted_to = ["//tools:k8"],
+    target_compatible_with = ["@platforms//os:linux"],
     deps = [
         ":python_init",
         "//external:python-gflags",
@@ -86,7 +86,7 @@
         "extended_lqr.py",
     ],
     legacy_create_init = False,
-    restricted_to = ["//tools:k8"],
+    target_compatible_with = ["@platforms//os:linux"],
     deps = [
         ":python_init",
         "//external:python-gflags",
@@ -99,6 +99,7 @@
 py_library(
     name = "python_init",
     srcs = ["__init__.py"],
+    target_compatible_with = ["@platforms//os:linux"],
     visibility = ["//visibility:public"],
     deps = ["//y2014/control_loops:python_init"],
 )
diff --git a/y2014/control_loops/shooter/BUILD b/y2014/control_loops/shooter/BUILD
index ed95317..9f71e95 100644
--- a/y2014/control_loops/shooter/BUILD
+++ b/y2014/control_loops/shooter/BUILD
@@ -8,6 +8,7 @@
         "shooter_goal.fbs",
     ],
     gen_reflections = 1,
+    target_compatible_with = ["@platforms//os:linux"],
 )
 
 flatbuffer_cc_library(
@@ -19,6 +20,7 @@
     includes = [
         "//frc971/control_loops:control_loops_fbs_includes",
     ],
+    target_compatible_with = ["@platforms//os:linux"],
 )
 
 flatbuffer_cc_library(
@@ -27,6 +29,7 @@
         "shooter_output.fbs",
     ],
     gen_reflections = 1,
+    target_compatible_with = ["@platforms//os:linux"],
 )
 
 flatbuffer_cc_library(
@@ -35,6 +38,7 @@
         "shooter_status.fbs",
     ],
     gen_reflections = 1,
+    target_compatible_with = ["@platforms//os:linux"],
 )
 
 genrule(
@@ -46,6 +50,7 @@
         "unaugmented_shooter_motor_plant.h",
     ],
     cmd = "$(location //y2014/control_loops/python:shooter) $(OUTS)",
+    target_compatible_with = ["@platforms//os:linux"],
     tools = [
         "//y2014/control_loops/python:shooter",
     ],
@@ -67,6 +72,7 @@
     linkopts = [
         "-lm",
     ],
+    target_compatible_with = ["@platforms//os:linux"],
     deps = [
         ":shooter_goal_fbs",
         ":shooter_output_fbs",
@@ -85,6 +91,7 @@
         "shooter_lib_test.cc",
     ],
     data = ["//y2014:config"],
+    target_compatible_with = ["@platforms//os:linux"],
     deps = [
         ":shooter_goal_fbs",
         ":shooter_lib",
@@ -103,6 +110,7 @@
     srcs = [
         "shooter_main.cc",
     ],
+    target_compatible_with = ["@platforms//os:linux"],
     deps = [
         ":shooter_lib",
         "//aos:init",
diff --git a/y2014/queues/BUILD b/y2014/queues/BUILD
index dba212d..294e2be 100644
--- a/y2014/queues/BUILD
+++ b/y2014/queues/BUILD
@@ -8,6 +8,7 @@
         "auto_mode.fbs",
     ],
     gen_reflections = 1,
+    target_compatible_with = ["@platforms//os:linux"],
 )
 
 flatbuffer_cc_library(
@@ -16,4 +17,5 @@
         "hot_goal.fbs",
     ],
     gen_reflections = 1,
+    target_compatible_with = ["@platforms//os:linux"],
 )