Fix ApplyRules misfires on weird paths, gotos don't include gc buffers

build_file.cpp

@@ -279,6 +279,8 @@ function SkipPath(s)
         if not slash_eaten then break end
     end
 
+    if #cells == 0 then return s end
+
     local skip_size = input_s:len() - s:len()
     local path = input_s:sub(1, skip_size)
     return s, path, drive, cells
@@ -297,6 +299,8 @@ end
 
 function MatchWindowsPath(_s)
     local s, file_path, drive = SkipPath(_s)
+    if not file_path then return nil end
+
     if not drive then
         local d = GetActiveMainWindowBufferDir()
         file_path = d..'/'..file_path