Checking if your kit is complete...
Looks good
Writing Makefile for Math::Int64
cp lib/Math/Int64.pm blib/lib/Math/Int64.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 Int64.xs > Int64.xsc && mv Int64.xsc Int64.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=\"0.03\" -DXS_VERSION=\"0.03\" -fPIC -I/home/cpanrun/ia64-lp64/build/5.6.1/lib/5.6.1/IA64.ARCHREV_0-thread-multi-64all/CORE -DINT64_BACKEND_DOUBLE Int64.c
Int64.xs:18:6: #error "no int64 parsing function available from C library"
make: *** [Int64.o] Error 1