foreign-library doesn't respect pkgconfig-depends

[mniip]

When building C sources of a foreign-library, no cflags from pkgconfig-depends libraries are passed to the compiler. (Even though those libraries do have cflags, and it works fine in a regular library and cc-options is passed alright)

[23Skidoo]

/cc @edsko @ezyang

[dmwit]

Just ran into this myself. If you'd like a minimal example, make a test.c with just #include <lua.h> and put this in test.cabal:

cabal-version:      3.0
name:               test
version:            0.1.0.0

foreign-library test
    type: native-shared
    c-sources: test.c
    pkgconfig-depends: lua-5.1

This results in the following error on my machine, which goes away if I explicitly include the output of pkg-config in a cc-options: field:

test.c:1:10: error:
     fatal error: lua.h: No such file or directory