$ make
/usr/bin/perl -I/usr/lib/perl5/5.6.1/i386-linux -I/usr/lib/perl5/5.6.1 /usr/lib/perl5/5.6.1/ExtUtils/xsubpp  -typemap /usr/lib/perl5/5.6.1/ExtUtils/typemap test_c.xs > test_c.xsc && mv test_c.xsc test_c.c
Error: 'double **' not in typemap in test_c.xs, line 8
make: *** [test_c.c] Error 1