Need to revisit library size optimizations (https://www.zverovich.net/2020/05/21/reducing-library-size.html) since there was a bit of a regression compared to 7.0:

% clang++ -std=c++17  -I include -O2 -DNDEBUG test.cc src/format.cc
% strip a.out
% ls -l a.out
-rwxr-xr-x  1 viz  staff  193960 May 20 11:50 a.out

For comparison 7.0 generates

-rwxr-xr-x  1 viz  staff  127472 May 20 11:53 a.out

with the latest clang and libc++. Looks like some of the regression is due to newer clang and standard library.