perl.o: In function `call_perl_cat': undefined reference to `Perl_Gthr_key_ptr'

When compiliing exim, if you get errors similar to:

perl.o: In function `call_perl_cat':
perl.c:(.text+0x14): undefined reference to `Perl_Gthr_key_ptr'
perl.c:(.text+0x26): undefined reference to `Perl_Tstack_sp_ptr'
perl.c:(.text+0x50): undefined reference to `Perl_Gthr_key_ptr'
perl.c:(.text+0x62): undefined reference to `Perl_push_scope'
perl.c:(.text+0x6e): undefined reference to `Perl_Gthr_key_ptr'
perl.c:(.text+0x80): undefined reference to `Perl_Ttmps_floor_ptr'

one found solution is to edit your Local/Makefile, and change the lines that say:

HAVE_ICONV=yes
#CFLAGS=-O -I/usr/local/include
#EXTRALIBS_EXIM=-L/usr/local/lib -liconv

and replace them with:

HAVE_ICONV=no
#CFLAGS=-O -I/usr/local/include
EXTRALIBS_EXIM=-L/usr/local/lib -liconv

You can also try removing the -libiconv from the list.