Update the ActivePerl/gcc-3.4 hack for EUMM 7.04

Starting from this version, PERL_ARCHIVE is quoted so we can no longer set
it to the empty string. Instead, we remove all occurrences of PERL_ARCHIVE
in the linking step section of the Makefile, which is OK since we specify
the perl DLL in other variables. This new technique is still valid for
older versions of EUMM.