Remove Windows-related GN build configuration

build/config/BUILD.gn

Index: build/config/BUILD.gn
diff --git a/build/config/BUILD.gn b/build/config/BUILD.gn
index f28f0cf8ee9e4ff9ee58656f62a080189a68083b..07395cb49ceab3200764a3e516bbae591fc5a385 100644
--- a/build/config/BUILD.gn
+++ b/build/config/BUILD.gn
@@ -287,14 +287,8 @@ config("debug") {
     defines += [ "DYNAMIC_ANNOTATIONS_PREFIX=NACL_" ]
   }
 
-  if (is_win) {
-    if (disable_iterator_debugging) {
-      # Iterator debugging is enabled by the compiler on debug builds, and we
-      # have to tell it to turn it off.
-      defines += [ "_HAS_ITERATOR_DEBUGGING=0" ]
-    }
-  } else if (is_linux && !is_android && current_cpu == "x64" &&
-             !disable_iterator_debugging) {
+  if (is_linux && !is_android && current_cpu == "x64" &&
+      !disable_iterator_debugging) {
     # Enable libstdc++ debugging facilities to help catch problems early, see
     # http://crbug.com/65151 .
     # TODO(phajdan.jr): Should we enable this for all of POSIX?
@@ -327,41 +321,7 @@ config("release") {
 
 # This config defines the default libraries applied to all targets.
 config("default_libs") {
-  if (is_win) {
-    # TODO(brettw) this list of defaults should probably be smaller, and
-    # instead the targets that use the less common ones (e.g. wininet or
-    # winspool) should include those explicitly.
-    libs = [
-      "advapi32.lib",
-      "comdlg32.lib",
-      "dbghelp.lib",
-      "delayimp.lib",
-      "dnsapi.lib",
-      "gdi32.lib",
-      "kernel32.lib",
-      "msimg32.lib",
-      "odbc32.lib",
-      "odbccp32.lib",
-      "ole32.lib",
-      "oleaut32.lib",
-      "psapi.lib",
-      "shell32.lib",
-      "shlwapi.lib",
-      "user32.lib",
-      "usp10.lib",
-      "uuid.lib",
-      "version.lib",
-      "wininet.lib",
-      "winmm.lib",
-      "winspool.lib",
-      "ws2_32.lib",
-
-      # Please don't add more stuff here. We should actually be making this
-      # list smaller, since all common things should be covered. If you need
-      # some extra libraries, please just add a libs = [ "foo.lib" ] to your
-      # target that needs it.
-    ]
-  } else if (is_android) {
+  if (is_android) {
     # Android uses -nostdlib so we need to add even libc here.
     libs = [
       # TODO(brettw) write a version of this, hopefully we can express this