Export of internal Abseil changes

--
034c30a00c64d93b9fcbc9d99a0a33801544d741 by Gennadiy Rozental <rogeeff@google.com>:

Split private handle interfaces accessor into a separate target with private visibility.

PiperOrigin-RevId: 310391488

--
6f6ca869309b17900b90849e08488ce7f7b0193a by Derek Mauro <dmauro@google.com>:

Remove __CLANG_SUPPORT_DYN_ANNOTATION__, which is a symbol defined by us
to be true in all builds

PiperOrigin-RevId: 310385325

--
ed5c1880c86973c000e826a3006b38e53ab3ed52 by Samuel Benzaquen <sbenza@google.com>:

Add tests to exercise extreme width and precision, and fix the overflows from
it.

PiperOrigin-RevId: 310224957
GitOrigin-RevId: 034c30a00c64d93b9fcbc9d99a0a33801544d741
Change-Id: I6c89a3c89ae92fa617c696044148ce9a79bcdda8

absl/flags/BUILD.bazel

@@ -40,6 +40,7 @@ cc_library(
     deps = [
         ":config",
         ":handle",
+        ":marshalling",
         ":registry",
         "//absl/base",
         "//absl/base:config",
@@ -143,8 +144,6 @@ cc_library(
         "//absl/flags:__pkg__",
     ],
     deps = [
-        ":config",
-        ":marshalling",
         "//absl/base:config",
         "//absl/base:core_headers",
         "//absl/base:fast_type_id",
@@ -153,6 +152,22 @@ cc_library(
     ],
 )
 
+cc_library(
+    name = "private_handle_accessor",
+    srcs = [
+        "internal/private_handle_accessor.cc",
+    ],
+    hdrs = [
+        "internal/private_handle_accessor.h",
+    ],
+    copts = ABSL_DEFAULT_COPTS,
+    linkopts = ABSL_DEFAULT_LINKOPTS,
+    visibility = [
+        "//absl/flags:__pkg__",
+    ],
+    deps = [":handle"],
+)
+
 cc_library(
     name = "registry",
     srcs = [
@@ -171,6 +186,7 @@ cc_library(
     deps = [
         ":config",
         ":handle",
+        ":private_handle_accessor",
         "//absl/base:config",
         "//absl/base:core_headers",
         "//absl/base:raw_logging_internal",
@@ -222,6 +238,7 @@ cc_library(
         ":flag_internal",
         ":handle",
         ":path_util",
+        ":private_handle_accessor",
         ":program_name",
         ":registry",
         "//absl/base:config",
@@ -263,6 +280,7 @@ cc_library(
         ":flag",
         ":flag_internal",
         ":handle",
+        ":private_handle_accessor",
         ":program_name",
         ":registry",
         ":usage",
@@ -289,6 +307,7 @@ cc_test(
         ":config",
         ":flag",
         ":handle",
+        ":private_handle_accessor",
         ":registry",
         "//absl/memory",
         "//absl/strings",