C++17 is the default now.

Test: builds
Change-Id: I6814455e9ad2cdcf99ad66de38a3ad0bfb440d80
diff --git a/adb/Android.bp b/adb/Android.bp
index e994075..ae8e386 100644
--- a/adb/Android.bp
+++ b/adb/Android.bp
@@ -25,7 +25,6 @@
         "-Wvla",
     ],
     rtti: true,
-    cpp_std: "gnu++17",
 
     use_version_lib: true,
 
@@ -72,7 +71,7 @@
                 "-DUNICODE=1",
                 "-D_UNICODE=1",
 
-                // -std=gnu++11 doesn't set _GNU_SOURCE on Windows.
+                // Unlike on Linux, -std=gnu++ doesn't set _GNU_SOURCE on Windows.
                 "-D_GNU_SOURCE",
 
                 // MinGW hides some things behind _POSIX_SOURCE.