+!GROK!THIS!
+
+## In the following, dollars and backticks do not need the extra backslash.
+$spitshell >>runtests <<'!NO!SUBS!'
+
+export PATH || (echo "OOPS, this isn't sh. Desperation time. I will feed myself to sh."; sh $0; kill $$)
+
+# Avoid "warning: jobserver unavailable: using -j1." warnings under GNU make.
+# When gmake -j N spawns a child, it passes
+# MAKEFLAGS=" --jobserver-fds=3,4 -j".
+# in the environment. Also, if make recognises that the child is another
+# make (e.g. it's invoked as $(MAKE) or +command), it keeps open fd's 3
+# and 4 to allow the child process to access the job server. Otherwise,
+# those fd's aren't kept open.
+# In the case where one does 'make -j 16 test_harness', this script is
+# called with MAKEFLAGS set, but fd's 3 and 4 closed. Later when
+# descendents of this script run cpan/ExtUtils-Constant/t/Constant.t
+# which itelf invokes make, the warnings ensue.