[build] Remove runpath from build host from shared ICU libraries on linux

[finagolfin]

I suggested the --enable-rpath flag in #40340 to add $ORIGIN more than a year ago, but I didn't realize it also adds the libdir to the runpath:

> find swift-DEVELOPMENT-SNAPSHOT-2023-03-10-a-ubuntu20.04/usr/ -name "lib*\.so*"|xargs readelf -d|ag "File:|runpath"|ag /home/ -B1
File: swift-DEVELOPMENT-SNAPSHOT-2023-03-10-a-ubuntu20.04/usr/lib/liblldb.so.13.0.0git
 0x000000000000001d (RUNPATH)            Library runpath: [$ORIGIN/../lib:/home/build-user/build/buildbot_linux/llvm-linux-x86_64/./lib:/home/build-user/build/buildbot_linux/swift-linux-x86_64/lib/swift/linux:$ORIGIN/../lib/swift/linux]
File: swift-DEVELOPMENT-SNAPSHOT-2023-03-10-a-ubuntu20.04/usr/lib/liblldb.so
 0x000000000000001d (RUNPATH)            Library runpath: [$ORIGIN/../lib:/home/build-user/build/buildbot_linux/llvm-linux-x86_64/./lib:/home/build-user/build/buildbot_linux/swift-linux-x86_64/lib/swift/linux:$ORIGIN/../lib/swift/linux]
File: swift-DEVELOPMENT-SNAPSHOT-2023-03-10-a-ubuntu20.04/usr/lib/swift/linux/libicuucswift.so
 0x000000000000001d (RUNPATH)            Library runpath: [$ORIGIN:/home/build-user/build/buildbot_linux/swift-linux-x86_64/lib/swift/linux/x86_64]
File: swift-DEVELOPMENT-SNAPSHOT-2023-03-10-a-ubuntu20.04/usr/lib/swift/linux/libicuucswift.so.65
 0x000000000000001d (RUNPATH)            Library runpath: [$ORIGIN:/home/build-user/build/buildbot_linux/swift-linux-x86_64/lib/swift/linux/x86_64]
File: swift-DEVELOPMENT-SNAPSHOT-2023-03-10-a-ubuntu20.04/usr/lib/swift/linux/libicudataswift.so
 0x000000000000001d (RUNPATH)            Library runpath: [$ORIGIN:/home/build-user/build/buildbot_linux/swift-linux-x86_64/lib/swift/linux/x86_64]
File: swift-DEVELOPMENT-SNAPSHOT-2023-03-10-a-ubuntu20.04/usr/lib/swift/linux/libicui18nswift.so.65.1
 0x000000000000001d (RUNPATH)            Library runpath: [$ORIGIN:/home/build-user/build/buildbot_linux/swift-linux-x86_64/lib/swift/linux/x86_64]
File: swift-DEVELOPMENT-SNAPSHOT-2023-03-10-a-ubuntu20.04/usr/lib/swift/linux/libicui18nswift.so.65
 0x000000000000001d (RUNPATH)            Library runpath: [$ORIGIN:/home/build-user/build/buildbot_linux/swift-linux-x86_64/lib/swift/linux/x86_64]
File: swift-DEVELOPMENT-SNAPSHOT-2023-03-10-a-ubuntu20.04/usr/lib/swift/linux/libicudataswift.so.65.1
 0x000000000000001d (RUNPATH)            Library runpath: [$ORIGIN:/home/build-user/build/buildbot_linux/swift-linux-x86_64/lib/swift/linux/x86_64]
File: swift-DEVELOPMENT-SNAPSHOT-2023-03-10-a-ubuntu20.04/usr/lib/swift/linux/libicudataswift.so.65
 0x000000000000001d (RUNPATH)            Library runpath: [$ORIGIN:/home/build-user/build/buildbot_linux/swift-linux-x86_64/lib/swift/linux/x86_64]
File: swift-DEVELOPMENT-SNAPSHOT-2023-03-10-a-ubuntu20.04/usr/lib/swift/linux/libicuucswift.so.65.1
 0x000000000000001d (RUNPATH)            Library runpath: [$ORIGIN:/home/build-user/build/buildbot_linux/swift-linux-x86_64/lib/swift/linux/x86_64]
File: swift-DEVELOPMENT-SNAPSHOT-2023-03-10-a-ubuntu20.04/usr/lib/swift/linux/libicui18nswift.so
 0x000000000000001d (RUNPATH)            Library runpath: [$ORIGIN:/home/build-user/build/buildbot_linux/swift-linux-x86_64/lib/swift/linux/x86_64]
File: swift-DEVELOPMENT-SNAPSHOT-2023-03-10-a-ubuntu20.04/usr/lib/liblldb.so.13git
 0x000000000000001d (RUNPATH)            Library runpath: [$ORIGIN/../lib:/home/build-user/build/buildbot_linux/llvm-linux-x86_64/./lib:/home/build-user/build/buildbot_linux/swift-linux-x86_64/lib/swift/linux:$ORIGIN/../lib/swift/linux]
File: swift-DEVELOPMENT-SNAPSHOT-2023-03-10-a-ubuntu20.04/usr/lib/clang/13.0.0/lib/linux/libclang_rt.memprof-x86_64.so
 0x000000000000001d (RUNPATH)            Library runpath: [$ORIGIN/../lib:/home/build-user/build/buildbot_linux/llvm-linux-x86_64/./lib]
File: swift-DEVELOPMENT-SNAPSHOT-2023-03-10-a-ubuntu20.04/usr/lib/clang/13.0.0/lib/linux/libclang_rt.ubsan_minimal-x86_64.so
 0x000000000000001d (RUNPATH)            Library runpath: [$ORIGIN/../lib:/home/build-user/build/buildbot_linux/llvm-linux-x86_64/./lib

See if this fixes it by using the more traditional LDFLAGS instead.

@bnbarham, please run the CI on this and I'll check that it works.

[bnbarham]

@swift-ci please test

[finagolfin]

Strangely, the flag got chomped down to -Wl,-rpath=RIGIN, I guess it interpreted it as the bash variable $O:

clang++ -O3 -fPIC -W -Wall -pedantic -Wpointer-arith -Wwrite-strings -Wno-long-long -std=c++11  -Qunused-arguments -Wno-parentheses-equality -Wglobal-constructors -Wl,-rpath=RIGIN   -shared -Wl,-Bsymbolic -Wl,-soname -Wl,libicutuswift.so.65 -o ../../lib/libicutuswift.so.65.1 filestrm.o package.o pkgitems.o swapimpl.o toolutil.o unewdata.o collationinfo.o denseranges.o ucm.o ucmstate.o uoptions.o uparse.o ucbuf.o xmlparser.o writesrc.o pkg_icu.o pkg_genc.o pkg_gencmn.o ppucd.o flagparser.o filetools.o udbgutil.o dbgutil.o ucln_tu.o -L../../lib -licui18nswift -L../../lib -licuucswift -L../../stubdata -licudataswift -lpthread -lm

I hate these bash escaping rules, let's try the three-slash variant.

[finagolfin]

@mhjacobson, if you're still up, please run the CI on this.

[mhjacobson]

@swift-ci please smoke test

[finagolfin]

Sigh, that didn't work either.

[finagolfin]

Found the magic incantation that appears to work, after testing it locally.

@bnbarham, please run the CI again and I will add an integration test next, to make sure this doesn't regress again.

[bnbarham]

@swift-ci please test

[finagolfin]

OK, CI passed now that the rpath was set properly, and I checked the build log to make sure it's set to the right value.

This is ready for review and merge, @bnbarham.

[bnbarham]

If this should stay a shared library this seems reasonable enough to me. Though it seems like the only thing that uses this now is foundation? In which case... maybe we should just statically link it?

[finagolfin]

I am not sure about the considerations that go into making such a change. For one, ICU uses different licenses than Foundation, which might then require some legal vetting.

I'm just trying to clean up all these CI runpaths leaking into the final toolchain, not going to attempt a bigger change like that, though it may make sense one day.