Checking out a clean tree today (commit: ) I can no longer build HEAD. Here's what I did:

cd ghc

./sync-all --no-dph get

cp mk/build.mk.sample mk/build.mk

# Uncomment devel2 in mk/build.mk

./boot && ./configure --with-gcc=/usr/local/bin/gcc-4.9

make

Here's the result:

gcc -E -m64 -DPROFILING -DTHREADED_RTS -DDEBUG -Irts/dist/build -m64 -fno-stack-protector -Wall -Wextra -Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations -Winline -Waggregate-return -Wpointer-arith -Wmissing-noreturn -Wnested-externs -Wredundant-decls -Iincludes -Iincludes/dist -Iincludes/dist-derivedconstants/header -Iincludes/dist-ghcconstants/header -Irts -Irts/dist/build -DCOMPILING_RTS -fno-strict-aliasing -fno-common -DDTRACE -O2 -fomit-frame-pointer -DRtsWay=\"rts_v\" -Wno-strict-prototypes -Wno-inline -finline-limit=2500 -MM -x c rts/sm/Compact.c -MF rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.bit
clang: error: unknown argument: '-finline-limit=2500' [-Wunused-command-line-argument-hard-error-in-future]
clang: note: this will be a hard error (cannot be downgraded to a warning) in the future
make[1]: *** [rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm] Error 1

More context:

sed -e 's|\\|/|g' -e 's| /$| \\|' -e "1s|\.o|\.o|" -e "1s|^|rts/sm/|" -e "1s|rts/|rts/dist/build/|" -e "1s|dist/build/dist/build|dist/build|g" -e "s|/Users/tibbe/src/ghc/||g" rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.bit >> rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.tmp && sed -e 's|\\|/|g' -e 's| /$| \\|' -e "1s|\.o|\.dyn_o|" -e "1s|^|rts/sm/|" -e "1s|rts/|rts/dist/build/|" -e "1s|dist/build/dist/build|dist/build|g" -e "s|/Users/tibbe/src/ghc/||g" rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.bit >> rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.tmp && sed -e 's|\\|/|g' -e 's| /$| \\|' -e "1s|\.o|\.l_o|" -e "1s|^|rts/sm/|" -e "1s|rts/|rts/dist/build/|" -e "1s|dist/build/dist/build|dist/build|g" -e "s|/Users/tibbe/src/ghc/||g" rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.bit >> rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.tmp && sed -e 's|\\|/|g' -e 's| /$| \\|' -e "1s|\.o|\.debug_o|" -e "1s|^|rts/sm/|" -e "1s|rts/|rts/dist/build/|" -e "1s|dist/build/dist/build|dist/build|g" -e "s|/Users/tibbe/src/ghc/||g" rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.bit >> rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.tmp && sed -e 's|\\|/|g' -e 's| /$| \\|' -e "1s|\.o|\.thr_o|" -e "1s|^|rts/sm/|" -e "1s|rts/|rts/dist/build/|" -e "1s|dist/build/dist/build|dist/build|g" -e "s|/Users/tibbe/src/ghc/||g" rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.bit >> rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.tmp && sed -e 's|\\|/|g' -e 's| /$| \\|' -e "1s|\.o|\.thr_debug_o|" -e "1s|^|rts/sm/|" -e "1s|rts/|rts/dist/build/|" -e "1s|dist/build/dist/build|dist/build|g" -e "s|/Users/tibbe/src/ghc/||g" rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.bit >> rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.tmp && sed -e 's|\\|/|g' -e 's| /$| \\|' -e "1s|\.o|\.thr_l_o|" -e "1s|^|rts/sm/|" -e "1s|rts/|rts/dist/build/|" -e "1s|dist/build/dist/build|dist/build|g" -e "s|/Users/tibbe/src/ghc/||g" rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.bit >> rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.tmp && sed -e 's|\\|/|g' -e 's| /$| \\|' -e "1s|\.o|\.debug_dyn_o|" -e "1s|^|rts/sm/|" -e "1s|rts/|rts/dist/build/|" -e "1s|dist/build/dist/build|dist/build|g" -e "s|/Users/tibbe/src/ghc/||g" rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.bit >> rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.tmp && sed -e 's|\\|/|g' -e 's| /$| \\|' -e "1s|\.o|\.thr_dyn_o|" -e "1s|^|rts/sm/|" -e "1s|rts/|rts/dist/build/|" -e "1s|dist/build/dist/build|dist/build|g" -e "s|/Users/tibbe/src/ghc/||g" rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.bit >> rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.tmp && sed -e 's|\\|/|g' -e 's| /$| \\|' -e "1s|\.o|\.thr_debug_dyn_o|" -e "1s|^|rts/sm/|" -e "1s|rts/|rts/dist/build/|" -e "1s|dist/build/dist/build|dist/build|g" -e "s|/Users/tibbe/src/ghc/||g" rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.bit >> rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.tmp && sed -e 's|\\|/|g' -e 's| /$| \\|' -e "1s|\.o|\.l_dyn_o|" -e "1s|^|rts/sm/|" -e "1s|rts/|rts/dist/build/|" -e "1s|dist/build/dist/build|dist/build|g" -e "s|/Users/tibbe/src/ghc/||g" rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.bit >> rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.tmp && sed -e 's|\\|/|g' -e 's| /$| \\|' -e "1s|\.o|\.thr_l_dyn_o|" -e "1s|^|rts/sm/|" -e "1s|rts/|rts/dist/build/|" -e "1s|dist/build/dist/build|dist/build|g" -e "s|/Users/tibbe/src/ghc/||g" rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.bit >> rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.tmp && true
gcc -E -m64 -DPROFILING -DTHREADED_RTS -DDEBUG -Irts/dist/build -m64 -fno-stack-protector -Wall -Wextra -Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations -Winline -Waggregate-return -Wpointer-arith -Wmissing-noreturn -Wnested-externs -Wredundant-decls -Iincludes -Iincludes/dist -Iincludes/dist-derivedconstants/header -Iincludes/dist-ghcconstants/header -Irts -Irts/dist/build -DCOMPILING_RTS -fno-strict-aliasing -fno-common -DDTRACE -O2 -fomit-frame-pointer -DRtsWay=\"rts_v\" -Wno-strict-prototypes -Wno-inline -finline-limit=2500 -MM -x c rts/sm/Compact.c -MF rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm.bit
clang: error: unknown argument: '-finline-limit=2500' [-Wunused-command-line-argument-hard-error-in-future]
clang: note: this will be a hard error (cannot be downgraded to a warning) in the future
make[1]: *** [rts/dist/build/.depend-v-dyn-l-debug-thr-thr_debug-thr_l-debug_dyn-thr_dyn-thr_debug_dyn-l_dyn-thr_l_dyn.c_asm] Error 1
make: *** [all] Error 2

-- Johan