Add prebuilt/win/v8_debug.lib (#1249)

The windows debug build was broken due to libc link errors.

.gn

@@ -30,6 +30,10 @@ default_args = {
   # for now. See http://clang.llvm.org/docs/ControlFlowIntegrity.html
   is_cfi = false
 
+  # Disabled due to CRT linking problems in Windows when using prebuilt V8.
+  # Works in other configurations.
+  is_component_build = false
+
   symbol_level = 1
   treat_warnings_as_errors = true
   rust_treat_warnings_as_errors = true

libdeno/BUILD.gn

@@ -54,7 +54,11 @@ v8_static_library("libdeno") {
     } else if (is_linux) {
       libs = [ "//prebuilt/linux64/libv8.a" ]
     } else if (is_win) {
-      libs = [ "//prebuilt/win/v8.lib" ]
+      if (is_debug) {
+        libs = [ "//prebuilt/win/v8_debug.lib" ]
+      } else {
+        libs = [ "//prebuilt/win/v8.lib" ]
+      }
     } else {
       assert(false, "We don't have prebuilt binaries for this platform yet.")
     }

prebuilt/win/v8_debug.lib.sha1

@@ -0,0 +1 @@
+e080ce76661b4d90f6e7879e58273d64344a9680

tools/prebuilt.py

@@ -5,12 +5,16 @@ from third_party import tp, google_env
 
 def download_v8_prebuilt():
     if sys.platform == 'win32':
-        sha1_file = "prebuilt/win/v8.lib.sha1"
+        download_prebuilt("prebuilt/win/v8.lib.sha1")
+        # TODO Ideally we wouldn't have to download both builds of V8.
+        download_prebuilt("prebuilt/win/v8_debug.lib.sha1")
     elif sys.platform.startswith('linux'):
-        sha1_file = "prebuilt/linux64/libv8.a.sha1"
+        download_prebuilt("prebuilt/linux64/libv8.a.sha1")
     elif sys.platform == 'darwin':
-        sha1_file = "prebuilt/mac/libv8.a.sha1"
+        download_prebuilt("prebuilt/mac/libv8.a.sha1")
 
+
+def download_prebuilt(sha1_file):
     run([
         "python",
         tp('depot_tools/download_from_google_storage.py'),