Move sync generics to their own packages

The presence of multiple packages in a single directory sometimes
confuses `go mod`, producing output like:
  go: downloading gvisor.dev/gvisor v0.0.0-20210601174640-77dc0f5bc94d
  $GOMODCACHE/gvisor.dev/gvisor@v0.0.0-20210601174640-77dc0f5bc94d/pkg/linewriter/linewriter.go:21:2: found packages sync (aliases.go) and seqatomic (generic_atomicptr_unsafe.go) in $GOMODCACHE/gvisor.dev/gvisor@v0.0.0-20210601174640-77dc0f5bc94d/pkg/sync
  imports.go:67:2: found packages tcp (accept.go) and rcv (rcv_test.go) in $GOMODCACHE/gvisor.dev/gvisor@v0.0.0-20210601174640-77dc0f5bc94d/pkg/tcpip/transport/tcp

PiperOrigin-RevId: 376956213

1 files changed, 45 insertions, 0 deletions

diff --git a/pkg/sync/seqatomic/BUILD b/pkg/sync/seqatomic/BUILD
new file mode 100644
index 000000000..60f79ab54
--- /dev/null
+++ b/pkg/sync/seqatomic/BUILD
@@ -0,0 +1,45 @@
+load("//tools:defs.bzl", "go_library", "go_test")
+load("//tools/go_generics:defs.bzl", "go_template", "go_template_instance")
+
+package(licenses = ["notice"])
+
+go_template(
+    name = "generic_seqatomic",
+    srcs = ["generic_seqatomic_unsafe.go"],
+    types = [
+        "Value",
+    ],
+    visibility = ["//:sandbox"],
+    deps = [
+        ":sync",
+        "//pkg/gohacks",
+    ],
+)
+
+go_template_instance(
+    name = "seqatomic_int",
+    out = "seqatomic_int_unsafe.go",
+    package = "seqatomic",
+    suffix = "Int",
+    template = ":generic_seqatomic",
+    types = {
+        "Value": "int",
+    },
+)
+
+go_library(
+    name = "seqatomic",
+    srcs = ["seqatomic_int_unsafe.go"],
+    deps = [
+        "//pkg/gohacks",
+        "//pkg/sync",
+    ],
+)
+
+go_test(
+    name = "seqatomic_test",
+    size = "small",
+    srcs = ["seqatomic_test.go"],
+    library = ":seqatomic",
+    deps = ["//pkg/sync"],
+)