Before the change the following command did not work:
$ nix develop -i --impure --expr 'with import <nixpkgs> { system = "i686-linux"; }; (buildFHSUserEnv { name = "t"; targetPkgs = ps: with ps; [ libmpc stdenv.cc ]; }).env'
$ ld -lmpc -o a
ld: cannot find -lmpc: No such file or directory
It is expected to work as `NIX_LDFLAGS` does contain valid values:
$ echo $NIX_LDFLAGS
-L/usr/lib -L/usr/lib32
Note that for `gcc` it does work:
$ printf "int main(){}" | gcc -x c - -lmpc -o a
It happens because `HOST` role is enabled for `cc`:
$ echo $NIX_CC_WRAPPER_TARGET_HOST_i686_unknown_linux_gnu
1
But not for `BINTOOLS`:
$ echo $NIX_BINTOOLS_WRAPPER_TARGET_HOST_i686_unknown_linux_gnu
<empty>
The change adds BINTOOLS role and fixes linking:
$ nix develop -i --impure --expr 'with import ~/nm { system = "i686-linux"; }; (buildFHSUserEnv { name = "t"; targetPkgs = ps: with ps; [ libmpc stdenv.cc ]; }).env'
$ printf "int main(){}" | gcc -x c - -lmpc -o a
$ ld -lmpc -o a
ld: warning: cannot find entry symbol _start; not setting start address
