[Support] Use HAVE_DLOPEN to guard dlopen(3) usage
[Support] Use HAVE_DLOPEN to guard dlopen(3) usage

Summary:
The usage was previously guarded by HAVE_DLFCN. This breaks on Android with
LLVM_BUILD_STATIC as the platform does not provide a static version of libdl.
Using HAVE_DLOPEN fixes it as the code will only get used if we are actually able
to link an executable using dlopen.

Reviewers: rafael, beanz

Subscribers: tberghammer, danalbert, llvm-commits

Differential Revision: https://reviews.llvm.org/D26504

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@288246 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-llvm,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,apple/swift-llvm