configure differences & build failure

configure: WARNING:
          There are some differences between the toolchain configured by "configure" (hadrian/cfg/default.target) and the toolchain configured by the "ghc-toolchain" program (hadrian/cfg/default.target.ghc-toolchain).
          18c18
< , tgtHsCPreprocessor = HsCpp {hsCppProgram = Program {prgPath = "/usr/bin/gcc", prgFlags = ["-E","-undef","-traditional"]}}
---
> , tgtHsCPreprocessor = HsCpp {hsCppProgram = Program {prgPath = "/usr/bin/gcc", prgFlags = ["-E","-undef","-traditional","-Wno-invalid-pp-token","-Wno-unicode","-Wno-trigraphs"]}}
20c20
< { ccLinkProgram = Program {prgPath = "/usr/bin/gcc", prgFlags = ["-fuse-ld=gold"]}
---
> { ccLinkProgram = Program {prgPath = "/usr/bin/gcc", prgFlags = ["-fuse-ld=gold","-Wl,--no-as-needed"]}
22c22
< , ccLinkSupportsCompactUnwind = True
---
> , ccLinkSupportsCompactUnwind = False
          Don't worry! This won't affect your ghc in any way.
          However, in a near future, we will move to configuring toolchains with "ghc-toolchain" by default, so you might have discovered a future bug.
          In light of it, if you've spotted this difference, please report a GHC bug at
                https://www.haskell.org/ghc/reportabug