Fix dropping from finder Lp1822424

[daschuer]

https://bugs.launchpad.net/mixxx/+bug/1822424

This is essentially a backport of
qt/qtbase@be5cfa9

It converts a reference file URL to a file path Url using objective C

[daschuer]

Undefined symbols for architecture x86_64:
  "_OBJC_CLASS_$_NSString", referenced from:
      objc-class-ref in filepathurl.o
  "_objc_msgSend", referenced from:
      stringFromNSString(NSString const*) in filepathurl.o
      urlFromNSURL(NSURL const*) in filepathurl.o
      ensureFilePathUrl(QUrl const&) in filepathurl.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

I guess I am missing a linker command.
Who knows how to solve this?

[ferranpujolcamins]

This patch fixes the build for me.
addFoundation.patch.zip

[ferranpujolcamins]

And I can confirm this fixes the drag and drop issue both for library tracks and new tracks.

[daschuer]

All green :-) Thank you.
Can we merge this and finally release 2.1.8?

[daschuer]

@ferranpujolcamins or @uklotzde: Can you have a look? I want to release 2.1.8 including this soon.

[uklotzde]

"FilePathURL" is a very generic name for a platform-specific and version-dependent workaround. How about renaming this to "OSXFilePathUrl" or "OSXFilePathUrlBackport"?

[uklotzde]

A reference of the Qt version from which this has been copied/backported might be helpful. The plain path even doesn't reveal that this is actually source code from Qt. Please use an URL.

[daschuer]

Done

[uklotzde]

LGTM