sizeof(long) and universal builds

[Mojca Miklavec]

Hi,

While checking some patches of a library I decided to try whether the
library would build universally. The configure.ac part contains:

    AC_COMPILE_CHECK_SIZEOF([long])

and that happily fails with

    checking size of long... configure: error: cannot determine a size for long

when setting

    CXXFLAGS="-arch i386 -arch x86_64"

What's the correct way to handle universal builds in that respect? Or
is it that is simply cannot be done?

Thank you,
    Mojca


PS: here's the relevant commit:
https://github.com/gdraheim/zziplib/commit/75ddc796529b191437514be2bbf6a2f561a74a6f