make; make -j8 sometimes fails

[jgross@mit.edu]

BarnOwl's build process does not seem to be thread safe. I've seen it fail with

  CCLD   zcrypt
  CCLD   barnowl.bin
perlconfig.o: In function `owl_perl_xs_init':
/afs/athena.mit.edu/user/j/g/jgross/Programs/barnowl/perlconfig.c:14: undefined reference to `boot_BarnOwl'

and also with

  GEN    varstubs.c
  GEN    perlglue.c
  GEN    owl_prototypes.h.new
Failed to load or import from ExtUtils::ParseXS (version 2.2002). Please check that ExtUtils::ParseXS is installed correctly and that the newest version will be found in your @INC path: "report_error_count" is not exported by the ExtUtils::ParseXS module
Can't continue after import errors at /mit/barnowl/arch/amd64_deb60/perl/lib/perl5/ExtUtils/xsubpp line 6
make: *** [perlglue.c] Error 9
make: *** Waiting for unfinished jobs....