[MacPorts] #56288: port:leveldb : minor upgrade with build system fixes and tcmalloc variant

[MacPorts]

#56288: port:leveldb : minor upgrade with build system fixes and tcmalloc variant
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  Reporter:  RJVB     |      Owner:  (none)
      Type:  update   |     Status:  new
  Priority:  Normal   |  Milestone:
 Component:  ports    |    Version:
Resolution:           |   Keywords:  haspatch
      Port:  leveldb  |
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Comment (by RJVB):

 I'd argue against that. Tcmalloc does indeed replace the system malloc but
 it's also a *lot* faster - which is why leveldb uses it in the first
 place. Currently leveldb is a dependency only of QtWebEngine and QtWebKit
 (AFAICT) and there it clearly doesn't pose a problem (supposing official
 builds of Chromium-based browsers use a standard leveldb build).

 That's why I proposed a build variant and I've even hesitated making it
 the default because I have just no way of knowing if the deadlock I was
 seeing (NOT in an existing, unmodified port) wasn't in fact triggered by
 an issue in my code. WebEngine is slow enough as it is, so it would
 certainly benefit from any optimisation it can get. Has there ever been a
 report of problems caused by tcmalloc?

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Ticket URL: <https://trac.macports.org/ticket/56288#comment:2>
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