For FreeBSD, pkg-config reports paths in /usr/local instead of /usr/local/$target

[schodet]

Checklist

• I've looked through the issues and pull requests for similar reports

Describe your issue

Trying to cross-compile a project using bindgen, the package I depend on is found, but the reported path is wrong.

It turns out that when using pkg-config, the library is found thanks to PKG_CONFIG_PATH variable, but the flags returned do not include the target in path.

When entering the container:

# pkg-config --cflags openssl
-I/usr/local/include
# ls /usr/local/include
(nothing)
#

The project I try to build is using rrd, for which I have an open PR to fix the build: cygnus9/rrd-rust#17

This works on a real FreeBSD host.

I am not familiar with the concept of sysroot, so I may miss something.

What target(s) are you cross-compiling for?

x86_64-unknown-freebsd

Which operating system is the host (e.g computer cross is on) running?

• macOS
• Windows
• Linux / BSD
• other OS (specify in description)

What architecture is the host?

• x86_64 / AMD64
• arm32
• arm64 (including Mac M1)

What container engine is cross using?

• docker
• podman
• other container engine (specify in description)

cross version

cross 0.2.5

Example

git clone https://github.com/schodet/rrd-rust.git -b pkg-config-include-path
cd rrd-rust/librrd-sys
edit Cross.toml
cross build --target x86_64-unknown-freebsd

With Cross.toml:

[target.x86_64-unknown-freebsd]
pre-build = ["""
export FREEBSD_MIRROR=$(/freebsd-fetch-best-mirror.sh) &&
/freebsd-setup-packagesite.sh &&
/freebsd-install-package.sh pkgconf rrdtool
"""]

Result:

...
src/gen/wrapper.h:1:10: fatal error: 'rrd.h' file not found

Additional information / notes

No response