I just tried to grab the latest GHC code so that I can test a bug fix for IO manager on OS X, but I ran into build errors. The failing command was: gcc -E -m32 -m32 -fno-stack-protector -Ilibraries/integer-gmp/gmp -Ilibraries/integer-gmp/mkGmpDerivedConstants/dist -MM libraries/integer-gmp/mkGmpDerivedConstants/mkGmpDerivedConstants.c -MF libraries/integer-gmp/mkGmpDerivedConstants/dist/build/.depend.c_asm.bit libraries/integer-gmp/mkGmpDerivedConstants/mkGmpDerivedConstants.c:15:17: error: gmp.h: No such file or directory It looks like it couldn't find gmp.h Looking over the build reports, I see a recent build on FreeBSD failed for exactly the same reason: http://darcs.haskell.org/ghcBuilder/builders/pgj/1016.html I checked some older (with commits up to March 29, 2013) build trees and I see that in libraries/integer-gmp/gmp there are files like gmp.h and libgmp.a that are not present in my latest build tree. Anyone know what's up here and how to fix this? -Andi