Can't cross-compile gtk2, gtk3 (NetBSD 10.1, amd64 -> i386)

[pl <pl%szwajn.net@localhost>]

Hi y'all,
Neither cross-compilation of gtk2 or gtk3 for i386 on my amd64 machine succeeds, in case of gtk2 it doesn't find cairo-xlib:
--- ze snip ---
[...]
checking for CAIRO_BACKEND... no
configure: error: Package requirements (cairo-xlib >= 1.6) were not met:

Package 'cairo-xlib' not found

Consider adjusting the PKG_CONFIG_PATH environment variable if you
installed software in a non-standard prefix.

Alternatively, you may set the environment variables CAIRO_BACKEND_CFLAGS
and CAIRO_BACKEND_LIBS to avoid the need to call pkg-config.
See the pkg-config man page for more details.
*** Error code 1

Stop.
make[2]: stopped in /usr/pkgsrc/x11/gtk2
*** Error code 1

Stop.
make[1]: stopped in /usr/pkgsrc/x11/gtk2
*** Error code 1

Stop.
make: stopped in /usr/pkgsrc/x11/gtk2
--- end of snip ---
(I have only x11 and cups options enabled (only "x11" is on by default))

And gtk3 fails on x11/libXft:
--- ze snip ---
Making all in man
Making all in src
--- libXft.la ---
  CCLD     libXft.la
/usr/obj/tooldir.NetBSD-10.1-amd64/lib/gcc/i486--netbsdelf/10.5.0/../../../../i486--netbsdelf/bin/ld: skipping incompatible /tmp/pkgsrc/x11/libXft/work.NetBSD-10.0-i386/.buildlink/lib/libXrender.so when searching for -lXrender
/usr/obj/tooldir.NetBSD-10.1-amd64/lib/gcc/i486--netbsdelf/10.5.0/../../../../i486--netbsdelf/bin/ld: skipping incompatible /tmp/pkgsrc/x11/libXft/work.NetBSD-10.0-i386/.buildlink/lib/libXrender.a when searching for -lXrender
/usr/obj/tooldir.NetBSD-10.1-amd64/lib/gcc/i486--netbsdelf/10.5.0/../../../../i486--netbsdelf/bin/ld: skipping incompatible /tmp/pkgsrc/x11/libXft/work.NetBSD-10.0-i386/.x11-buildlink/lib/libXrender.so when searching for -lXrender
/usr/obj/tooldir.NetBSD-10.1-amd64/lib/gcc/i486--netbsdelf/10.5.0/../../../../i486--netbsdelf/bin/ld: skipping incompatible /tmp/pkgsrc/x11/libXft/work.NetBSD-10.0-i386/.x11-buildlink/lib/libXrender.a when searching for -lXrender
/usr/obj/tooldir.NetBSD-10.1-amd64/lib/gcc/i486--netbsdelf/10.5.0/../../../../i486--netbsdelf/bin/ld: cannot find -lXrender
/usr/obj/tooldir.NetBSD-10.1-amd64/lib/gcc/i486--netbsdelf/10.5.0/../../../../i486--netbsdelf/bin/ld: skipping incompatible /tmp/pkgsrc/x11/libXft/work.NetBSD-10.0-i386/.buildlink/lib/libX11.so when searching for -lX11
/usr/obj/tooldir.NetBSD-10.1-amd64/lib/gcc/i486--netbsdelf/10.5.0/../../../../i486--netbsdelf/bin/ld: skipping incompatible /tmp/pkgsrc/x11/libXft/work.NetBSD-10.0-i386/.buildlink/lib/libX11.a when searching for -lX11
/usr/obj/tooldir.NetBSD-10.1-amd64/lib/gcc/i486--netbsdelf/10.5.0/../../../../i486--netbsdelf/bin/ld: skipping incompatible /tmp/pkgsrc/x11/libXft/work.NetBSD-10.0-i386/.x11-buildlink/lib/libX11.so when searching for -lX11
/usr/obj/tooldir.NetBSD-10.1-amd64/lib/gcc/i486--netbsdelf/10.5.0/../../../../i486--netbsdelf/bin/ld: skipping incompatible /tmp/pkgsrc/x11/libXft/work.NetBSD-10.0-i386/.x11-buildlink/lib/libX11.a when searching for -lX11
/usr/obj/tooldir.NetBSD-10.1-amd64/lib/gcc/i486--netbsdelf/10.5.0/../../../../i486--netbsdelf/bin/ld: cannot find -lX11
collect2: error: ld returned 1 exit status
*** [libXft.la] Error code 1

make[2]: stopped in /tmp/pkgsrc/x11/libXft/work.NetBSD-10.0-i386/libXft-2.3.8/src
1 error

make[2]: stopped in /tmp/pkgsrc/x11/libXft/work.NetBSD-10.0-i386/libXft-2.3.8/src

make[1]: stopped in /tmp/pkgsrc/x11/libXft/work.NetBSD-10.0-i386/libXft-2.3.8

make: stopped in /tmp/pkgsrc/x11/libXft/work.NetBSD-10.0-i386/libXft-2.3.8
*** Error code 2

Stop.
make[2]: stopped in /usr/pkgsrc/x11/libXft
*** Error code 1

Stop.
make[1]: stopped in /usr/pkgsrc/x11/libXft
*** Error code 1

Stop.
make: stopped in /usr/pkgsrc/x11/gtk3
--- end of snip ---

Both GTK2 and GTK3 fail at configure stage

Here my /etc/mk.conf:
MAKE_JOBS=		12
WRKOBJDIR=		/tmp/pkgsrc

USE_CROSS_COMPILE?=	yes
CROSS_MACHINE_ARCH=	i386
CROSS_OPSYS=		NetBSD
CROSS_OS_VERSION=	10.0
CROSS_OPSYS_VERSION=	100000
CROSS_LOWER_OPSYS=	netbsd
CROSS_OBJECT_FMT=	ELF

CROSS_DESTDIR=		/usr/obj/destdir.i386
TOOLDIR=		/usr/obj/tooldir.NetBSD-10.1-amd64

CROSS_LOWER_OPSYS_VERSUFFIX=
CROSS_LOWER_OS_VARIANT=
CROSS_LOWER_VARIANT_VERSION=
CROSS_LOWER_VENDOR=

PKG_DEFAULT_OPTIONS=	cups -avahi -dbus -bluray -wayland -nls -kerberos -info
PKG_OPTIONS.cairo=	-xcb -x11
(end)

Host is NetBSD 10.1 amd64 on bhyve, pkgsrc wasn't bootstrapped, toolchain and system (together w/ X11) were built by "./build.sh -m i386 -j 12 -x distribution".
And that setup works for compiling CUPS, Perl, Python, GnuTLS and so on.

So yeah, what can I do to make gtk2/3 build?
--
pl <pl%szwajn.net@localhost>