Checking if your kit is complete...
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Writing Makefile for Crypt::Square
cp Square.pm blib/lib/Crypt/Square.pm
/home/cpanrun/ia64-lp64/build/5.6.1/bin/perl -I/home/cpanrun/ia64-lp64/build/5.6.1/lib/5.6.1/IA64.ARCHREV_0-thread-multi-64all -I/home/cpanrun/ia64-lp64/build/5.6.1/lib/5.6.1 /home/cpanrun/ia64-lp64/build/5.6.1/lib/5.6.1/ExtUtils/xsubpp  -typemap /home/cpanrun/ia64-lp64/build/5.6.1/lib/5.6.1/ExtUtils/typemap -typemap typemap Square.xs > Square.xsc && mv Square.xsc Square.c
gcc -c -I. -DUSE_REENTRANT_API -D_POSIX_C_SOURCE=199506L -D_HPUX_SOURCE -mlp64 -L/lib/hpux64 -DUINT32_MAX_BROKEN -fPIC -fno-strict-aliasing -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -O   -DVERSION=\"1.0.0\" -DXS_VERSION=\"1.0.0\" -fPIC -I/home/cpanrun/ia64-lp64/build/5.6.1/lib/5.6.1/IA64.ARCHREV_0-thread-multi-64all/CORE  Square.c
In file included from Square.xs:5:
_square.c:1474:4: #error "Either LITTLE_ENDIAN or BIG_ENDIAN must be defined"
make: *** [Square.o] Error 1