Changes

[clangd] Define out-of-line availability checks
Summary: Initial availability checks for performing define out-of-line
code action, which is a refactoring that will help users move
function/method definitions from headers to implementation files.
Proposed implementation only checks whether we have an interesting
selection, namely function name or full function definition/body.
Reviewers: hokein
Subscribers: mgorny, ilya-biryukov, MaskRay, jkorous, arphaman,
usaxena95, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D69266

[clangd] Define out-of-line initial apply logic
Summary: Initial implementation for apply logic, replaces function body
with a semicolon in source location and copies the full function
definition into target location.
Will handle qualification of return type and function name in following
patches to keep the changes small.
Reviewers: hokein
Subscribers: ilya-biryukov, MaskRay, jkorous, arphaman, usaxena95,
cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D69298

[clangd] Define out-of-line qualify return value
Summary: Return type might need qualification if insertion context
doesn't have the same decls visible as the source context.
This patch adds qualification for return value to cover such cases.
Reviewers: hokein
Subscribers: ilya-biryukov, MaskRay, jkorous, arphaman, usaxena95,
cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D70535

[clangd] Define out-of-line qualify function name
Summary: When moving function definitions to a different context, the
function name might need a different spelling, for example in the header
it might be:
``` namespace a {
 void foo() {}
}
```
And we might want to move it into a context which doesn't have
`namespace a` as a parent, then we must re-spell the function name, i.e:
``` void a::foo() {}
```
This patch implements a version of this which ignores using namespace 
declarations in the source file.
Reviewers: hokein
Subscribers: ilya-biryukov, MaskRay, jkorous, arphaman, usaxena95,
cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D70656

[lldb][NFC] Migrate to raw_ostream in ArchSpec::DumpTriple
Reviewers: labath, davide
Reviewed By: davide
Subscribers: clayborg, JDevlieghere, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D70979

Revert "Enable `-funwind-tables` flag when building libunwind"
This reverts commit b3fdf33ba6aa7ef80621696f74aaf2f6f8e1d1de.
This change broke building libunwind for Windows/MinGW, and broke on
aspect of the CMake tests in libunwind in general.
After set(CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY), CMake skips the
linking step in tests, but cmake/config-ix.cmake also does a few checks
for functions in libraries (looking for whether
-lc provides fopen and whether -ldl provides dladdr).
As CMake only tests building a static library, these tests incorrectly
succeed and CMake concludes "Looking for fopen in c - found" and
"Looking for dladdr in dl - found", while building then fails at the end
with errors about unable to find -lc and -ldl.

gn build: Merge 9f251eece46

[CodeGen][ObjC] Emit a primitive store to store a __strong field in
ExpandTypeFromArgs
This fixes a bug in IRGen where a call to `llvm.objc.storeStrong` was 
being emitted to initialize a __strong field of an uninitialized 
temporary struct, which caused crashes at runtime.
rdar://problem/51807365