$ORACLE_HOME/forms/lib32/make -f ins_forms.mk install
Got the following error:
ld: fatal: library -ljvm: not found
ld: fatal: File processing errors. No output written to frmbld
make: *** [frmbld] Error 1
Apparently no one else has ever reported this problem before...
Turns out the user's env didn't include LD_LIBRARY_PATH. Fixed that, and problem was solved.