* for host* parts you need to install linux-libc-dev:i386 on ubuntu-21.10
(not pulled by gcc-multilib already mentioned in meta-oe/README), otherwise
build for 32bit target will fail like this:

cortexa7t2hf-neon-vfpv4-oe-linux-gnueabi/luajit/2.1.0~beta3-210112-r0/git/src$ gcc -m32 -Wall -I. -DLUAJIT_TARGET=LUAJIT_ARCH_arm -DLJ_ARCH_HASFPU=1 -DLJ_ABI_SOFTFP=0 -isystem/OE/build/oe-core/tmp-glibc/work/cortexa7t2hf-neon-vfpv4-oe-linux-gnueabi/luajit/2.1.0~beta3-210112-r0/recipe-sysroot-native/usr/include -O2 -pipe -c -o host/minilua.o host/minilua.c
In file included from /usr/include/bits/errno.h:26,
from /usr/include/errno.h:28,
from host/minilua.c:40:
/usr/include/linux/errno.h:1:10: fatal error: asm/errno.h: No such file or directory
1 | #include <asm/errno.h>
| ^~~~~~~~~~~~~
compilation terminated.

while for 64bit taget it would build without -m32 and work fine without linux-libc-dev:i386:

cortexa7t2hf-neon-vfpv4-oe-linux-gnueabi/luajit/2.1.0~beta3-210112-r0/git/src$ gcc -Wall -I. -DLUAJIT_TARGET=LUAJIT_ARCH_arm -DLJ_ARCH_HASFPU=1 -DLJ_ABI_SOFTFP=0 -isystem/OE/build/oe-core/tmp-glibc/work/cortexa7t2hf-neon-vfpv4-oe-linux-gnueabi/luajit/2.1.0~beta3-210112-r0/recipe-sysroot-native/usr/include -O2 -pipe -c -o host/minilua.o host/minilua.c
<OK>

Signed-off-by: Martin Jansa <Martin.Jansa@...>
---
meta-oe/README | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/meta-oe/README b/meta-oe/README
index 98f671d7c2..a0a28189c6 100644
--- a/meta-oe/README
+++ b/meta-oe/README
@@ -15,7 +15,7 @@ e.g. on archlinux based distributions install prerequisites like below
pacman -S lib32-gcc-libs lib32-glibc

Ubuntu
-sudo apt-get install gcc-multilib
+sudo apt-get install gcc-multilib linux-libc-dev:i386

Send pull requests to openembedded-devel@... with '[meta-oe]' in the subject'

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2.32.0