Add win cross build script.

@gz83

build_win.sh

@@ -0,0 +1,28 @@
+#!/bin/bash
+
+# Copyright (c) 2022 Alex313031.
+
+YEL='\033[1;33m' # Yellow
+c0=$'\033[0m' # Reset Text
+bold=$'\033[1m' # Bold Text
+underline=$'\033[4m' # Underline Text
+
+displayHelp () {
+	printf "\n" &&
+	printf "${bold}${YEL}Script to build Thorium for Windows on Linux.${c0}\n" &&
+	printf "${underline}Usage${c0}: build_win.sh # (where # is number of jobs)\n" &&
+	printf "\n"
+}
+
+case $1 in
+	--help) displayHelp; exit 0;;
+esac
+
+printf "\n" &&
+printf "${YEL}Building Thorium...\n" &&
+printf "\n" &&
+tput sgr0 &&
+
+export NINJA_SUMMARIZE_BUILD=1 &&
+
+./misc/autoninja -C ~/chromium/src/out/thorium chrome chromedriver content_shell setup mini_installer -j$@