I'd like to build GHC, and all the base libs, with an extra flag supplied to cc (well gcc) and ld commands: I thought I could just add this to mk/build.mk: SRC_CC_OPTS = -mmacos-version-min=10.7 SRC_LD_OPTS = -mmacos-version-min=10.7 But this seems very inconsistently applied. For example: This part of the build of the RTS gets it: "inplace/bin/ghc-stage1" -optc-m64 -optc-fno-stack-protector *-optc-mmacosx-version-min=10.7* -optc-Wall -optc-Wextra -optc-Wstrict-prototypes -optc-Wmissing-prototypes -optc-Wmissing-declarations -optc-Winline -optc-Waggregate-return -optc-Wpointer-arith -optc-Wmissing-noreturn -optc-Wnested-externs -optc-Wredundant-decls -optc-Iincludes -optc-Iincludes/dist -optc-Iincludes/dist-derivedconstants/header -optc-Iincludes/dist-ghcconstants/header -optc-Irts -optc-Irts/dist/build -optc-DCOMPILING_RTS -optc-fno-strict-aliasing -optc-fno-common -optc-DBE_CONSERVATIVE -optc-DDTRACE -optc-O2 -optc-fomit-frame-pointer -optc-DRtsWay=\"rts_v\" -static -H32m -O -Iincludes -Iincludes/dist -Iincludes/dist-derivedconstants/header -Iincludes/dist-ghcconstants/header -Irts -Irts/dist/build -DCOMPILING_RTS -package-name rts -dcmm-lint -DDTRACE -i -irts -irts/dist/build -irts/dist/build/autogen -Irts/dist/build -Irts/dist/build/autogen -O2 -c rts/Hash.c -o rts/dist/build/Hash.o But this part doesn't: "inplace/bin/ghc-stage2" -hisuf dyn_hi -osuf dyn_o -hcsuf dyn_hc -fPIC -dynamic -H32m -O -hide-all-packages -i -iutils/haddock/driver -iutils/haddock/src -iutils/haddock/vendor/attoparsec-0.10.4.0 -iutils/haddock/dist/build -iutils/haddock/dist/build/autogen -Iutils/haddock/dist/build -Iutils/haddock/dist/build/autogen -optP-DIN_GHC_TREE -optP-include -optPutils/haddock/dist/build/autogen/cabal_macros.h -package Cabal-1.18.1.3 -package array-0.5.0.0 -package base-4.7.0.1 -package bytestring-0.10.4.0 -package containers-0.5.5.1 -package deepseq-1.3.0.2 -package directory-1.2.1.0 -package filepath-1.3.0.2 -package ghc-7.8.2.20140623 -package xhtml-3000.2.1 -funbox-strict-fields -Wall -fwarn-tabs -O2 -XHaskell2010 -no-user-package-db -rtsopts -odir utils/haddock/dist/build -hidir utils/haddock/dist/build -stubdir utils/haddock/dist/build -c utils/haddock/src/Haddock/Utf8.hs -o utils/haddock/dist/build/Haddock/Utf8.dyn_o I think it might have to do with the dyn_o and thr_o targets? So - Is there a better way to ensure these flags are applied? I suppose I could wrap gcc (clang) and ld.... but that seems ham-handed. - Mark