multiple definition in librand with parallel codegen

[msiemens]

When building rustc with parallel codegen, linking librand fails:

rustc: i686-w64-mingw32/stage0/bin/rustlib/i686-w64-mingw32/lib/librand
i686-w64-mingw32\stage0\bin\rustlib\i686-w64-mingw32\lib\rand-4e7c5e5c.1.o:(.rdata+0x2c0): multiple definition of `isaac::IsaacRng.Rng::next_u32::_MSG_FILE_LINE::hc349c9a6706e0477dMb'
i686-w64-mingw32\stage0\bin\rustlib\i686-w64-mingw32\lib\rand-4e7c5e5c.0.o:(.rdata+0x410): first defined here
i686-w64-mingw32\stage0\bin\rustlib\i686-w64-mingw32\lib\rand-4e7c5e5c.1.o:(.rdata+0x310): multiple definition of `isaac::Isaac64Rng.Rng::next_u64::_MSG_FILE_LINE::hc349c9a6706e0477Mgc'
i686-w64-mingw32\stage0\bin\rustlib\i686-w64-mingw32\lib\rand-4e7c5e5c.0.o:(.rdata+0x460): first defined here
i686-w64-mingw32\stage0\bin\rustlib\i686-w64-mingw32\lib\rand-4e7c5e5c.2.o:(.rdata+0x190): multiple definition of `isaac::IsaacRng.Rng::next_u32::_MSG_FILE_LINE::hc349c9a6706e0477dMb'
i686-w64-mingw32\stage0\bin\rustlib\i686-w64-mingw32\lib\rand-4e7c5e5c.0.o:(.rdata+0x410): first defined here
i686-w64-mingw32\stage0\bin\rustlib\i686-w64-mingw32\lib\rand-4e7c5e5c.2.o:(.rdata+0x1e0): multiple definition of `isaac::Isaac64Rng.Rng::next_u64::_MSG_FILE_LINE::hc349c9a6706e0477Mgc'
i686-w64-mingw32\stage0\bin\rustlib\i686-w64-mingw32\lib\rand-4e7c5e5c.0.o:(.rdata+0x460): first defined here
i686-w64-mingw32\stage0\bin\rustlib\i686-w64-mingw32\lib\rand-4e7c5e5c.3.o:(.rdata+0x2b50): multiple definition of `isaac::IsaacRng.Rng::next_u32::_MSG_FILE_LINE::hc349c9a6706e0477dMb'
i686-w64-mingw32\stage0\bin\rustlib\i686-w64-mingw32\lib\rand-4e7c5e5c.0.o:(.rdata+0x410): first defined here
i686-w64-mingw32\stage0\bin\rustlib\i686-w64-mingw32\lib\rand-4e7c5e5c.3.o:(.rdata+0x3bc0): multiple definition of `isaac::Isaac64Rng.Rng::next_u64::_MSG_FILE_LINE::hc349c9a6706e0477Mgc'
i686-w64-mingw32\stage0\bin\rustlib\i686-w64-mingw32\lib\rand-4e7c5e5c.0.o:(.rdata+0x460): first defined here
collect2.exe: error: ld returned 1 exit status

I'm using Windows 7 x64 with MSYS2

[HeroesGrave]

Also occurs on Arch Linux x86_64.

[emberian]

This doesn't reproduce anymore with pcwalton@c245c5b re-applied.

[msiemens]

@cmr: I tried to re-apply the commit too, but it still fails, this time in lib\core:

i686-pc-windows-gnu\stage0\bin\rustlib\i686-pc-windows-gnu\lib\core-4e7c5e5c.1.o:(.rdata+0x670): multiple definition of `iter::uint.Step::steps_between::_MSG_FILE_LINE::he1870d67ab684df6fMn'
i686-pc-windows-gnu\stage0\bin\rustlib\i686-pc-windows-gnu\lib\core-4e7c5e5c.0.o:(.rdata+0x200): first defined here
i686-pc-windows-gnu\stage0\bin\rustlib\i686-pc-windows-gnu\lib\core-4e7c5e5c.1.o:(.rdata+0x690): multiple definition of `iter::u8.Step::steps_between::_MSG_FILE_LINE::he1870d67ab684df6INn'
i686-pc-windows-gnu\stage0\bin\rustlib\i686-pc-windows-gnu\lib\core-4e7c5e5c.0.o:(.rdata+0x220): first defined here
i686-pc-windows-gnu\stage0\bin\rustlib\i686-pc-windows-gnu\lib\core-4e7c5e5c.1.o:(.rdata+0x6b0): multiple definition of `iter::u16.Step::steps_between::_MSG_FILE_LINE::he1870d67ab684df6bPn'
i686-pc-windows-gnu\stage0\bin\rustlib\i686-pc-windows-gnu\lib\core-4e7c5e5c.0.o:(.rdata+0x240): first defined here
i686-pc-windows-gnu\stage0\bin\rustlib\i686-pc-windows-gnu\lib\core-4e7c5e5c.1.o:(.rdata+0x6d0): multiple definition of `iter::u32.Step::steps_between::_MSG_FILE_LINE::he1870d67ab684df6EQn'
i686-pc-windows-gnu\stage0\bin\rustlib\i686-pc-windows-gnu\lib\core-4e7c5e5c.0.o:(.rdata+0x260): first defined here
i686-pc-windows-gnu\stage0\bin\rustlib\i686-pc-windows-gnu\lib\core-4e7c5e5c.1.o:(.rdata+0x6f0): multiple definition of `iter::int.Step::steps_between::_MSG_FILE_LINE::he1870d67ab684df67Rn'
... (and similar)

[alexcrichton]

I believe this was fixed at some point in the meantime in one of @nrc's patches, so closing as likely fixed.