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/build/5.8.2/bin/perl /home/cpanrun/ia64/build/5.8.2/lib/5.8.2/ExtUtils/xsubpp  -typemap /home/cpanrun/ia64/build/5.8.2/lib/5.8.2/ExtUtils/typemap  Int64.xs > Int64.xsc && mv Int64.xsc Int64.c
cc -c  -I. -D_POSIX_C_SOURCE=199506L -D_REENTRANT -Ae -D_HPUX_SOURCE -Wl,+vnocompatwarnings -DNO_HASH_SEED -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -fast +DSitanium2 +Ofltacc=strict   -DVERSION=\"0.03\" -DXS_VERSION=\"0.03\" +Z "-I/home/cpanrun/ia64/build/5.8.2/lib/5.8.2/IA64.ARCHREV_0-thread-multi/CORE"  -DINT64_BACKEND_DOUBLE Int64.c
Error 119: "Int64.xs", line 18 # #error "no int64 parsing function available from C library" 
    #    error "no int64 parsing function available from C library"
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
make: *** [Int64.o] Error 2