Invoking -v for clang during buildworld

While playing with -current on armv7 using a raspberry pi 2 v1.1 
an error crops up with recent kernels while building world:

++: error: linker command failed with exit code 1 (use -v to see invocation)
*** [clang.full] Error code 1

make[5]: stopped in /usr/freebsd-src/usr.bin/clang/clang

How does one invoke -v in this situation?

For the record, uname -a reports
FreeBSD www.zefox.com 13.0-CURRENT FreeBSD 13.0-CURRENT #6 main-c950-gff1a307801: Wed Jan 13 19:02:18 PST 2021     bob_at_www.zefox.com:/usr/obj/usr/freebsd-src/arm.armv7/sys/GENERIC-MMCCAM  arm

The present sources are a day or two newer.

Nothing is obviously wrong; swap usage is small, no warnings or errors on the console.

In past occurrences, an old kernel (pre-git) worked through the problem.
If a restart of make buildworld doesn't get past the stoppage I'll check again.

Thanks for reading,

bob prohaska