[root@ Crypt-IDEA-1.01]# perl Makefile.PL
Checking if your kit is complete...
Looks good
Writing Makefile for Crypt::IDEA
[root@ Crypt-IDEA-1.01]# make
cp IDEA.pod blib/lib/Crypt/IDEA.pod
cp IDEA.pm blib/lib/Crypt/IDEA.pm
/usr/local/bin/perl /usr/local/lib/perl5/5.8.0/ExtUtils/xsubpp  -typemap /usr/local/lib/perl5/5.8.0/ExtUtils/typemap -typemap typemap  IDEA.xs > IDEA.xsc && mv IDEA.xsc IDEA.c
Please specify prototyping behavior for IDEA.xs (see perlxs manual)
cc -c   -fno-strict-aliasing -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -I/usr/include/gdbm -O2   -DVERSION=\"1.01\" -DXS_VERSION=\"1.01\" -fpic "-I/usr/local/lib/perl5/5.8.0/i686-linux/CORE"   IDEA.c
IDEA.xs: In function `XS_Crypt__IDEA_crypt':
IDEA.xs:66: `sv_undef' undeclared (first use in this function)
IDEA.xs:66: (Each undeclared identifier is reported only once
IDEA.xs:66: for each function it appears in.)
make: *** [IDEA.o] Error 1