Roll build, buildtools, and V8

Unlanded attempt:
https://pdfium-review.googlesource.com/c/2410/

BUG=690088

Change-Id: I0bd3396426bd9faadb8c8dba2c2b7a7b9b52b178
Reviewed-on: https://pdfium-review.googlesource.com/2576
Reviewed-by: dsinclair <dsinclair@chromium.org>
Commit-Queue: Nicolás Peña <npm@chromium.org>
diff --git a/build_overrides/build.gni b/build_overrides/build.gni
index 61d7814..af65788 100644
--- a/build_overrides/build.gni
+++ b/build_overrides/build.gni
@@ -12,12 +12,12 @@
 
 # Variable that can be used to support multiple build scenarios, like having
 # Chromium specific targets in a client project's GN file etc.
-build_with_chromium = true
+build_with_chromium = false
 
 # Support different NDK locations in non-Chromium builds.
 default_android_ndk_root = "//third_party/android_ndk"
 default_android_ndk_version = "r12b"
-default_android_ndk_major_version = "12"
+default_android_ndk_major_version = 12
 
 # PDFium builds don't support building java targets.
 enable_java_templates = false
@@ -51,8 +51,9 @@
 
 if (use_system_xcode == "") {
   if (target_os == "mac") {
-    _result =
-        exec_script("//build/mac/should_use_hermetic_xcode.py", [], "value")
+    _result = exec_script("//build/mac/should_use_hermetic_xcode.py",
+                          [ target_os ],
+                          "value")
     use_system_xcode = _result == 0
   }
   if (target_os == "ios") {