swift234

[cmake] Add new option --extra-swift-options that enables one to pass cmake flags to specific libraries by pattern matching a regexp upon their name.

Often times one wants to pass certain flags to swift when building
specific libraries and not others. This has in the past required
manually modifying the cmake system. This new option allows one to use
string regexps based on the module_name of a library to enable and
disable various flags. The way this works is you pass the following into
build-script:

--extra-swift-options="${REGEX1};${FLAGS1_WITH_SEMICOLONS_ESCAPED}"
--extra-swift-options="${REGEX2};${FLAGS2_WITH_SEMICOLONS_ESCAPED}"
--extra-swift-options="${REGEX3};${FLAGS3_WITH_SEMICOLONS_ESCAPED}"
--extra-swift-options="${REGEX4};${FLAGS4_WITH_SEMICOLONS_ESCAPED}"
--extra-swift-options="${REGEX5};${FLAGS5_WITH_SEMICOLONS_ESCAPED}"

Every library that matches REGEPN will have FLAGSN_... appended to their
swift flags. For instance if I did the following:

build-script --extra-swift-options="Swift;-Xfrontend\;-sil-print-pass-name" --extra-swift-options='^Swift$;-Xllvm\;-debug-only=sil-arc-opts" ...

CMake will output the following:

-- Matched 'Swift' to module 'Swift'. Compiling Swift with special flags: -Xfrontend;-sil-print-pass-name
-- Matched '^Swift$' to module 'Swift'. Compiling Swift with special flags: -Xllvm;-debug-only=sil-arc-opts
-- Matched 'Swift' to module 'SwiftExperimental'. Compiling SwiftExperimental with special flags: -Xfrontend;-sil-print-pass-name
-- Matched 'Swift' to module 'SwiftStructures'. Compiling SwiftStructures with special flags: -Xfrontend;-sil-print-pass-name
-- Matched 'Swift' to module 'SwiftStructuresGraphBFS'. Compiling SwiftStructuresGraphBFS with special flags: -Xfrontend;-sil-print-pass-name

stating which regexp was matched, the module it was matched to and the
added flags. This ensures that one only gets matches for what one wants.

Swift SVN r24271