Cannot generate the GTAGS at windows platform

[LeoZhang-ATMEL]

Describe the bug
Cannot generate the GTAGS files on windows, looks like this issue was caused by missing the plat/win32/update_gtags.cmd files.

It could be fixed by manually adding the missing file with the below content.

$ cat plat/win32/update_gtags.cmd
@echo off
setlocal EnableExtensions EnableDelayedExpansion
rem ==========================================
rem PARSE ARGUMENTS
rem ==========================================
set GTAGS_EXE=gtags
set GTAGS_ARGS=%~4
set INCREMENTAL=
:ParseArgs
if [%1]==[] goto :DoneParseArgs
if [%1]==[-e] (
set GTAGS_EXE=%~2
shift
goto :LoopParseArgs
)
if [%1]==[--incremental] (
set INCREMENTAL=--incremental
shift
goto :LoopParseArgs
)
echo Invalid Argument: %1
goto :Usage
:LoopParseArgs
shift
goto :ParseArgs
:DoneParseArgs
rem ==========================================
rem GENERATE TAGS
rem ==========================================
echo Running gtags:
echo call %GTAGS_EXE% %INCREMENTAL% %GTAGS_ARGS%
call %GTAGS_EXE% %INCREMENTAL% %GTAGS_ARGS%
echo Done.
goto :EOF
rem ==========================================
rem USAGE
rem ==========================================
:Usage
echo Usage:
echo %~n0 ^<options^>
echo.
echo -e [exe=gtags]: The gtags executable to run.
echo -L [cmd=]: The file list command to run
echo.

[zoumi]

Why not create a PR?

[LeoZhang-ATMEL]

PR created, #330

[dean-ho]

I encounter same issue. Will it be fixed?

[retzzz]

I encounter same issue. But I remember when I use old version before the GTAGS can work.

[skywind3000]

please use my fork please: https://github.com/skywind3000/vim-gutentags
before my PR #336 get merged.

After 39dc3ee , gtags became unusable in gutentags because this commit requires a update_gtags.sh or update_gtags.cmd script to execute actual gtags command, but:

1. update_gtags.sh lacks of execution permission on Linux.
2. update_gtags.cmd is not provided.

So, after that commit, gtags is no longer usable in gutentags.

my update_gtags.cmd is modified from @LeoZhang-ATMEL 's version but add two thing:

1. better argument parsing
2. support newly added -L option.