boost: install fails with +openmpi: bootstrap compilation fails for `b2`

[Epoxid2 (Stephan Schmidt)]

The various Boost ports fail to install with +openmpi, on Monterey 12.5.1.

Appears to be an issue with bootstrap compilation of b2:

:info:configure Building B2 engine..
1421	:info:configure > cpp -DNDEBUG builtins.cpp class.cpp command.cpp compile.cpp constants.cpp cwd.cpp debug.cpp debugger.cpp execcmd.cpp execnt.cpp execunix.cpp filesys.cpp filent.cpp fileunix.cpp frames.cpp function.cpp glob.cpp hash.cpp hcache.cpp hdrmacro.cpp headers.cpp jam_strings.cpp jam.cpp jamgram.cpp lists.cpp make.cpp make1.cpp md5.cpp mem.cpp modules.cpp native.cpp object.cpp option.cpp output.cpp parse.cpp pathnt.cpp pathsys.cpp pathunix.cpp regexp.cpp rules.cpp scan.cpp search.cpp startup.cpp subst.cpp sysinfo.cpp timestamp.cpp variable.cpp w32_getreg.cpp modules/order.cpp modules/path.cpp modules/property-set.cpp modules/regex.cpp modules/sequence.cpp modules/set.cpp -o b2
1422	:info:configure cpp: fatal error: too many input files
1423	:info:configure compilation terminated.
1424	:info:configure > cp b2 bjam
1425	:info:configure cp: b2: No such file or directory
1426	:info:configure Failed to build B2 build engine