[commit: ghc] wip/angerman/llvmng's head updated: bump submodules (20454d0)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

Branch 'wip/angerman/llvmng' now includes:

     5229c43 Squashed 'hadrian/' changes from 438dc576e7..5ebb69ae1e
     506ba62 Merge commit '5229c43ccf77bcbffeced01dccb27398d017fa34'
     f11f252 Windows: Bump to GCC 7.2 for GHC 8.4
     ba2ae2c Adds cmm-sources to base
     426af53 Use LICENSE instead of ../LICENSE in the compiler.cabal file
     5f158bc circleci: Bump down thread count
     86c50a1 Declare proper spec version in `base.cabal`
     e3ec2e7 WIP on combined Step 1 and 3 for Trees That Grow, HsExpr
     0a85190 Fix a TyVar bug in the flattener
     f570000 A bit more tc-tracing
     47ad657 TTG3 Combined Step 1 and 3 for Trees That Grow
     f5dc8cc Add new mbmi and mbmi2 compiler flags
     6dfe982 StaticPointers: Clarify documentation
     5dea62f Adds rts/rts.cabal.in file
     8b1020e RTS: Disable warnings in ffi.h
     ea26162 CLabel: Clean up unused label types
     1aba27a CLabels: Remove CaseLabel
     383016b Add dump flag for timing output
     d9f0c24 rts: Fix gc timing
     d0a641a Allow the rts lib to be called rts-1.0
     3bed4aa Cabalify all the things
     e14945c Adjust AltCon Ord instance to match Core linter requirements.
     ec080ea users_guide: Fix "CancelSynchronousIo" casing
     c1fcd9b Squashed 'hadrian/' changes from 5ebb69a..fa3771f
     07ac921 Pull recent Hadrian changes from upstream
     2f46387 Detect overly long GC sync
     2da7813 Document -ddump-timings
     c729734 configure: Fix incorrect quoting
     12a7444 Adds -ghc-version flag to ghc.
     835d8dd GHC.Prim use virtual-modules
     bb11a2d Relocatable GHC
     f2502df [rts] ignore generated rts.cabal
     36bd24f Adds `-llvmng`
     f475c0b cleanup
     8116657 CodeGen, support memcpy
     21de524 Adds test
     20454d0 bump submodules