Merging r367837:

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r367837 | mstorsjo | 2019-08-05 13:57:06 +0200 (Mon, 05 Aug 2019) | 10 lines

[MinGW] Add an lld specific option for requesting to delay load libraries

With GNU tools, delayload is handled completely differently. (One
creates a specific delayload import library using dlltool and then
links against it instead of the normal import library.)

Instead of requiring using -Xlink=-delayload:lib.dll, we can provide
an lld specific option for this.

Differential Revision: https://reviews.llvm.org/D65728
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llvm-svn: 368134