llvm-config sometimes doesn't provide the correct include directory

[brson]

llvm-config --cxxflags looks like this for me:

-I/home/banderson/Dev/rust/src/llvm/include -I/home/banderson/Dev/rust/build/llvm/x86_64-unknown-linux-gnu/include  -D_DEBUG -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -O3 -fomit-frame-pointer -fno-exceptions -fno-rtti -fPIC -Woverloaded-virtual -Wcast-qual

Critically, our build depends on that first include directory, under the source tree, for rustllvm. In some environments llvm-config doesn't give us that information, probably because it isn't realizing that it's being run out of the build directory.

[brson]

There's a hack in mk/rustllvm.mk that adds it manually on windows. should be removed when we figure this out.

[emberian]

Still relevant.

[catamorphism]

Triage bump. I still see the hack, but don't know how to make progress with this.

[reem]

Triage. Hack still there, also unsure how to progress.

[steveklabnik]

Triage: same as what @reem said.

[steveklabnik]

Over a year later, my triage estimate is the same as it was last year.

[arielb1]

triage: ?

[kyrias]

Does anyone have a short example for reproducing this?

[joelgallant]

There's a hack in mk/rustllvm.mk that adds it manually on windows. should be removed when we figure this out.

@brson with the makefiles gone, is this still an issue or should this be looked into?

[alexcrichton]

Indeed I think this is no longer relevant!