Pull define for version out into v8-version-string.h and separate build target

BUILD.gn

Index: BUILD.gn
diff --git a/BUILD.gn b/BUILD.gn
index 0daea44e822dc5c6b2469e7acabf14192e05b0aa..b1153a62dcc3982bf6e8194fb6a83479ab59604e 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -851,6 +851,17 @@ if (v8_use_external_startup_data) {
   }
 }
 
+# This is split out to be a non-code containing target that the Chromium browser
+# DLL can depend upon to get only a version string.
+v8_source_set("v8_version") {
+  configs = [ ":internal_config" ]
+
+  sources = [
+    "include/v8-version-string.h",
+    "include/v8-version.h",
+  ]
+}
+
 v8_source_set("v8_base") {
   visibility = [ ":*" ]  # Only targets in this file can depend on this.
 
@@ -2189,6 +2200,7 @@ v8_source_set("v8_base") {
   deps = [
     ":v8_libbase",
     ":v8_libsampler",
+    ":v8_version",
   ]
 
   sources += [ v8_generated_peephole_source ]