Fix GN NaCl Debug build of base.

BUG=401761
TBR=brettw
CQ_EXTRA_TRYBOTS=tryserver.chromium.linux:android_chromium_gn_compile_dbg,android_chromium_gn_compile_rel;tryserver.chromium.win:win8_chromium_gn_rel,win8_chromium_gn_dbg;tryserver.chromium.mac:mac_chromium_gn_rel,mac_chromium_gn_dbg

Review URL: https://codereview.chromium.org/972203003

Cr-Original-Commit-Position: refs/heads/master@{#319987}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 9099f49130311a760ce3fe88b7782a5574e6ba9d

config/BUILD.gn

@@ -236,6 +236,10 @@ config("debug") {
     "WTF_USE_DYNAMIC_ANNOTATIONS=1",
   ]
 
+  if (is_nacl) {
+    defines += [ "DYNAMIC_ANNOTATIONS_PREFIX=NACL_" ]
+  }
+
   if (is_win) {
     if (disable_iterator_debugging) {
       # Iterator debugging is enabled by the compiler on debug builds, and we

config/compiler/BUILD.gn

@@ -157,7 +157,7 @@ config("compiler") {
     ]
   }
 
-  if (is_clang && !is_win) {
+  if (is_clang && !is_win && !is_nacl) {
     # This is here so that all files get recompiled after a clang roll and
     # when turning clang on or off. (defines are passed via the command line,
     # and build system rebuild things when their commandline changes). Nothing
@@ -726,6 +726,7 @@ config("default_warnings") {
   if (is_win) {
     cflags = [
       "/WX",  # Treat warnings as errors.
+
       # Warnings permanently disabled:
 
       # TODO(GYP) The GYP build doesn't have this globally enabled but disabled
@@ -780,6 +781,7 @@ config("default_warnings") {
       # have to turn off this warning (and be careful about how object
       # destruction happens in such cases).
       "/wd4611",
+
       # Warnings to evaluate and possibly fix/reenable later:
 
       "/wd4100",  # Unreferenced formal function parameter.