problem with building 64-bit binary of qpopper 4.1b14 on solaris

hello all,

i am having problems building qpopper 4.1b14 in 64-bit mode on  
solaris. the os is SXCE build 105 (x64) and Sun's Studio 12 compiler  
is used (Sun C 5.9 SunOS_i386 Patch 124868-07 2008/10/07).
configure's "--enable-64-bit" option is set and i can see a line in  
the output saying "Building 64-bit binary", however later on during  
make i get the following error:

cc   pop_dele.o pop_dropcopy.o  pop_get_command.o pop_get_subcommand.o  
pop_init.o  pop_last.o pop_list.o pop_log.o pop_lower.o  pop_msg.o  
pop_parse.o pop_pass.o pop_quit.o  pop_rset.o pop_send.o pop_stat.o  
pop_updt.o  pop_user.o pop_xtnd.o pop_xmit.o popper.o  pop_bull.o  
xtnd_xlst.o pop_uidl.o  pop_rpop.o pop_apop.o pop_auth.o pop_pope.o   
pop_extend.o scram.o hmac.o pop_util.o  get_sub_opt.o msg_ptr.o drac.o  
pop_config.o pop_tls.o  pop_tls_openssl.o pop_tls_sslplus.o  
sslplus_utils.o  main.o pop_cache.o genpath.o pop_sasl.o md5.o  
base64.o -o popper \
         ../mmangle/libmangle.a \
         -I../common ../common/libcommon.a \
         -lnsl -lsocket -lresolv -lmail    -lnsl  -lposix4 -lcrypt -L/ 
usr/lib -lssl -lcrypto -m64
ld: fatal: file pop_dele.o: wrong ELF class: ELFCLASS32
ld: fatal: file processing errors. No output written to popper
*** Error code 1
make: Fatal error: Command failed for target `popper'
Current working directory /root/sources/qpopper4.1b14/popper
*** Error code 1
make: Fatal error: Command failed for target `popper_server'

all other object files in the popper directory a 32-bit too:
base64.o:       ELF 32-bit LSB relocatable 80386 Version 1
drac.o:         ELF 32-bit LSB relocatable 80386 Version 1
genpath.o:      ELF 32-bit LSB relocatable 80386 Version 1
<snip>

any help will be appreciated,


greetings,

Stoyan Angelov