``` 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 ```