A few windows fixes.

backends.py

@@ -30,7 +30,7 @@ else:
     execute_wrapper = ''
 
 def ninja_quote(text):
-    return text.replace(' ', '$ ')
+    return text.replace(' ', '$ ').replace(':', '$:')
 
 def do_replacement(regex, line, confdata):
     match = re.search(regex, line)

environment.py

@@ -256,6 +256,8 @@ class VisualStudioCCompiler(CCompiler):
         return ['/c']
 
     def get_output_flags(self, target):
+        if target.endswith('.exe'):
+            return ['/Fe' + target]
         return ['/Fo' + target]
 
     def get_dependency_gen_flags(self, outtarget, outfile):