Make the SONAME of the monolithic libLLVM
configurable. This is part of enabling the creation
of libraries with consistent names between old
autotools-based builds, and new CMake builds.
This diff does not change the current naming
scheme, but it would be trivial to do so later.
This is in response to
also to enable Debian's LLVM packaging to move to
llvm_add_library now has SOVERSION and VERSION
options, which, if non-empty and not equal to "cmake-default",
will be set as properties on shared library targets.
The "cmake-default" special case is due to empty string
arguments not resulting in variables defined. This allows us
(a) defaults if SOVERSION/VERSION are unspecified (i.e. existing MAJOR.MINOR for SOVERSION, etc.)
(b) a means of using the CMake-default SOVERSION/VERSION (i.e. by passing "cmake-default")
There are two new user-configurable options:
LLVM_DYLIB_SOVERSION (defaults to $MAJOR.$MINOR) LLVM_DYLIB_VERSION (defaults to $PACKAGE_VERSION)
A follow-up will introduce configuration for the name of
the libLLVM shared library.