[gentoo-user] cross-emerge dev-lang/spidermonkey fails without obvious error

[Britaliope]

Hi,

I'm trying to crossbuild from AMD64 to aarch64, and so far i was able to
fix the issues on the way, but i am stuck with this one :

cross-emerging dev-lang/spidermonkey fails without any useful error :
end of build.log (full log is attached to this email) :

```
make[3]: Leaving directory
'/usr/aarch64-linux-gnu/tmp/portage/dev-lang/spidermonkey-78.5.0/work/build/js/src/jit'
make[2]: Leaving directory
'/usr/aarch64-linux-gnu/tmp/portage/dev-lang/spidermonkey-78.5.0/work/build'
make[1]: ***
[/usr/aarch64-linux-gnu/tmp/portage/dev-lang/spidermonkey-78.5.0/work/firefox-78.5.0/config/
recurse.mk:34: compile] Error 2
make[1]: Leaving directory
'/usr/aarch64-linux-gnu/tmp/portage/dev-lang/spidermonkey-78.5.0/work/build'
make: ***
[/usr/aarch64-linux-gnu/tmp/portage/dev-lang/spidermonkey-78.5.0/work/firefox-78.5.0/config/
rules.mk:392: default] Error 2
 * ERROR: dev-lang/spidermonkey-78.5.0::gentoo failed (compile phase):
 *   emake failed
 *
 * If you need support, post the output of `emerge --info
'=dev-lang/spidermonkey-78.5.0::gentoo'`,
 * the complete build log and the output of `emerge -pqv
'=dev-lang/spidermonkey-78.5.0::gentoo'`.
 * The complete build log is located at
'/usr/aarch64-linux-gnu/tmp/portage/dev-lang/spidermonkey-78.5.0/temp/build.log'.
 * The ebuild environment file is located at
'/usr/aarch64-linux-gnu/tmp/portage/dev-lang/spidermonkey-78.5.0/temp/environment'.
 * Working directory:
'/usr/aarch64-linux-gnu/tmp/portage/dev-lang/spidermonkey-78.5.0/work/build'
 * S:
'/usr/aarch64-linux-gnu/tmp/portage/dev-lang/spidermonkey-78.5.0/work/firefox-78.5.0/js/src'
```


#### Result of `emerge-aarch64-linux-gnu -pqv
'=dev-lang/spidermonkey-78.5.0::gentoo'` :
[ebuild  N    ] dev-lang/spidermonkey-78.5.0 to /usr/aarch64-linux-gnu/
USE="jit -debug -lto -test" CPU_FLAGS_ARM="(-neon)"


### Results of emerge-aarch64-linux-gnu --info
'=dev-lang/spidermonkey-78.5.0::gentoo' and full build log are attached.


Do you see anything that would help me to identify what caused this failure
?

Thanks in advance,
Bruno MATEU