Try llvm-config binaries with version suffix.

This allows us to pick up the newest available version on
several common Debian derivatives.

[Cherry-picked 2b4f49b4e from master.]
Search LLVM_ROOT_DIR before system directories.
Fold in MinGW Phobos test update.
Merge branch 'release-0.11.0'.

Conflicts:
	cmake/Modules/FindLLVM.cmake
	runtime/phobos
Merge branch 'vectordi'
Remove bogous DtoMemCpy assertion.

DtoMemCpy is called with identical pointer arguments in
some legal cases.
Minor array copy refactoring.
Do not generate invalid memcpy() for struct self assignment.

This catches only the most trivial case, need to investigate
this further.

See GitHub #385.
Rename TD_Confirm to TD_TypeInfo.

The old name probably was a reference to the fact that the
metadata node is used to _confirm_ that a metadata record
found by name really belongs to a given TypeInfo instance,
but I found it to be rather non-intuitive.
Removed tautological checks.

They were probably used during initial development of the
pass to be able to disable emission of the global reference
by setting TD_TypeInfo to -1.
Remove USE_METADATA.

It has been on by default for quite some time now.
Avoid emitting invalid IR for function type TypeInfo metadata.

This fixes LLVM debug builds of the DMD testsuite.
LDMD: Made error message on compiler execution error clearer.

It is also triggered when the compiler exits with a signal, etc.
DValue: Do not uselessly inherit from Object.
DValue: struct->class.

This is in line with an incoming upstream change making all
polymorphic structs classes, and also matches common coding
conventions.
Minor DVarValue refactoring.
Detab RTTIBuilder.
Downgraded accepts-invalid workaround error to assertion.

Bug 9268 was fixed in 2.062.
Store bools as i8.

I really hope we can refactor this to use a less leaky
abstraction later – it should at least be possible to merge
voidToI8 and i1ToI8.
Add debug info for enums.

Previously enums were reduced to the underlying type.
Now the symbolic constants can be used.