This is an auto-filled bug because media-libs/mesa calls nm directly.
The issue was originally discovered on x86, but it may be reproducible on other arches as well.
Attached build log and emerge --info.
To reproduce this issue you may want to temporarily move the /usr/bin/nm binary.
Created attachment 633568 [details]
build log and emerge --info
Created attachment 642006 [details]
Run-time dependency glproto found: YES 1.4.17
Run-time dependency dri2proto found: YES 2.8
Run-time dependency xxf86vm found: YES 1.1.4
Run-time dependency xcb-xfixes found: YES 1.14
Run-time dependency xcb-randr found: YES 1.14
Run-time dependency xrandr found: YES 1.5.2
Program nm found: NO
../mesa-20.1.0-rc4/meson.build:1731:2: ERROR: Program(s) ['nm'] not found or not executable
A full log can be found at /var/tmp/portage/media-libs/mesa-20.1.0_rc4/work/mesa-20.1.0-rc4-abi_x86_32.x86/meson-logs/meson-log.txt
Fixed by https://gitweb.gentoo.org/repo/gentoo.git/commit/eclass/meson.eclass?id=da03d40f146a646c38e75fd0a6fc299b5aeba505