Many thanks for your monklike patience- I should have found and read the README file. The cpan command still doesn't find the library, but proceeding with fixing the Makefile and running perl Makefile.PL and make, I now come up with:

sav_if/s_comput.h:662:4: error: #error Unsupported GNU C/C++ target hardware platform

This looks to me like a sophos rather than a perl bug or inavailability, the code causing this error being:

/*
 * Hardware platform.
 */

# if defined(__i386__)
#  define __SOPHOS_I386__
# elif (defined(__hppa__) && defined(_PA_RISC1_1))
#  define __SOPHOS_HP_PA__
# elif defined(__sparc__)
#  define __SOPHOS_SPARC__
# elif (defined(_POWER) || defined(__ppc__) || defined(__POWERPC__) ||
+ defined(__PPC__))
#  define __SOPHOS_POWERPC__
# elif (defined(TARGET_CPU_68K) || defined(__CFM68K__) || defined(m68k
+) || defined(_M_M68K))
#  define __SOPHOS_68000__
# elif defined(__alpha__)
#  define __SOPHOS_ALPHA__
# elif defined (__s390__)
#  define __SOPHOS_S390__
# elif defined(__VAX)
#  define __SOPHOS_VAX__
# else
#  error Unsupported GNU C/C++ target hardware platform
# endif
[download]

I don't understand this well, but I'll see what I can find out. Thanks again.

Ann