[static-stdlib] Explicit autolink for RegexParser in StringProcessing

[kateinoigakukun]

_RegexParser is used only in StringProcessing and it's imported with
@_implementationOnly.
Modules imported with @_implementationOnly are not autolinked, so build
system let the importer module how to link it. When building a shared
library, _RegexParser is already linked into StringProcessing. But when
building a static library, it's not. So we need to add autolink entry
explicitly.

Without this patch, compilation of source using regex feature with -static-stdlib would fail with the following error:

$ echo '_ = try Regex("x")' | swiftc - -static-stdlib
error: link command failed with exit code 1 (use -v to see invocation)
/usr/lib/swift_static/linux/libswift_StringProcessing.a(_StringProcessing.o):_StringProcessing.o:function $s17_StringProcessing5RegexV5MatchV6outputxvg: error: undefined reference to '$s12_RegexParser16TypeConstructionO5tuple2ofypxn_tSKRzyp7ElementRtzlFZ'
/usr/lib/swift_static/linux/libswift_StringProcessing.a(_StringProcessing.o):_StringProcessing.o:function $s17_StringProcessing8CompilerC11ByteCodeGenV8emitNode33_39AB0CA4F16DF29C6C8E2960922072B7LLyAA8TypedIntVyAA14_ValueRegisterOGSgAA7DSLTreeV0H0OKF: error: undefined reference to '$s12_RegexParser3ASTV14QuantificationV6AmountOMa'
/usr/lib/swift_static/linux/libswift_StringProcessing.a(_StringProcessing.o):_StringProcessing.o:function $s17_StringProcessing8CompilerC11ByteCodeGenV8emitNode33_39AB0CA4F16DF29C6C8E2960922072B7LLyAA8TypedIntVyAA14_ValueRegisterOGSgAA7DSLTreeV0H0OKF: error: undefined reference to '$s12_RegexParser3ASTV5GroupV4KindOMa'
/usr/lib/swift_static/linux/libswift_StringProcessing.a(_StringProcessing.o):_StringProcessing.o:function $s17_StringProcessing8CompilerC11ByteCodeGenV8emitNode33_39AB0CA4F16DF29C6C8E2960922072B7LLyAA8TypedIntVyAA14_ValueRegisterOGSgAA7DSLTreeV0H0OKF: error: undefined reference to '$s12_RegexParser11CaptureListVMa'
/usr/lib/swift_static/linux/libswift_StringProcessing.a(_StringProcessing.o):_StringProcessing.o:function $s17_StringProcessing8CompilerC11ByteCodeGenV8emitNode33_39AB0CA4F16DF29C6C8E2960922072B7LLyAA8TypedIntVyAA14_ValueRegisterOGSgAA7DSLTreeV0H0OKF: error: undefined reference to '$s12_RegexParser11UnsupportedVMa'
/usr/lib/swift_static/linux/libswift_StringProcessing.a(_StringProcessing.o):_StringProcessing.o:function $s17_StringProcessing8CompilerC11ByteCodeGenV8emitNode33_39AB0CA4F16DF29C6C8E2960922072B7LLyAA8TypedIntVyAA14_ValueRegisterOGSgAA7DSLTreeV0H0OKF: error: undefined reference to '$s12_RegexParser11UnsupportedVMa'
...

[kateinoigakukun]

@swift-ci Please smoke test

[kateinoigakukun]

@swift-ci Please smoke test

[Azoy]

Thanks!

[MaxDesiatov]

@Azoy would you mind if this is merged, or should we wait for more approvals?

[Azoy]

I’m fine with this being merged 🙂