hErrorMutex leaks if GDALAllRegister is not called

[Mateusz Łoskot]

This issue is of similar nature to #6139

Consider this minimal example:

int main()
{
    CPLError(CE_None, CPLE_AppDefined,
             "Expected, CPLError called to trigger hErrorMutex allocation");
    GDALDestroy();
    return 0;
}

If run under memory debugger, hErrorMutex will be reported as memory and kernel resource leak.

The issue is due to:

• CPLCleanupErrorMutex only called from GDALDriverManager destructor
• If GDALAllRegister is not called, there is no GDALDriverManager instance to destroy and clean up the mutex

Solution: call CPLCleanupErrorMutex from GDALDestroy to ensure the clean-up

[Mateusz Łoskot]

Fix the reported issue. Update test. (Fixing tab to space)

[Mateusz Łoskot]

Fix the reported issue. Update test.

[Mateusz Łoskot]

Sorry for dup .patch. They're exactly the same.

[Mateusz Łoskot]

In 38080:

Fix hErrorMutex leak if GDALAllRegister is not called

Fixes #6868

[Mateusz Łoskot]

I'd like to merge it also into branches/2.2, may I?

[Mateusz Łoskot]

In 38084:

Merged revision(s) 38080, 38083 from trunk:
Fix hErrorMutex leak if GDALAllRegister is not called

Fixes #6868
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Untabify r38080
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