[tz] Use GST abbreviation for Asia/Dubai, Asia/Muscat

[Brian Inglis]

On 2017-07-12 15:40, Paul Eggert wrote:
> "GST" was my invention, and as I far as I know it is not typically used in
> English-language sources (other than those derived from tzdata). 

Also used in Canada since 1991 as the abbreviation for the federal value added
Goods and Services Tax, which likely produces most web search hits now.

Your first use was in 1993g for Pacific/Guam ST +1000, Asia/[various] Gulf ST
+0400, with various prefixes and offsets for [South]America/[various] Guiana ST,
and subsequently for Atlantic/South_Georgia ST -0200, all but the latter
predating widespread web search engines.

-- 
Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada