Error upgrading to exim 4.69

[angelf9]

I tried to update exim to from 4.67 to 4.69 using this tutorial:
http://help.directadmin.com/item.php?id=126

However, sometime after executing :

rpmbuild --rebuild --force da_exim-4.69-1.src.rpm

I get this error:

gcc dkim-exim.c

awk '{ print ($1+1) }' cnumber.h > cnumber.temp
rm -f cnumber.h; mv cnumber.temp cnumber.h
gcc version.c
rm -f exim
gcc -o exim
rfc2047.o: In function `rfc2047_decode2':
rfc2047.c:(.text+0x395): undefined reference to `libiconv_open'
rfc2047.c:(.text+0x45a): undefined reference to `libiconv'
rfc2047.c:(.text+0x539): undefined reference to `libiconv_close'
collect2: ld returned 1 exit status
make[1]: *** [exim] Error 1
make[1]: Leaving directory `/usr/src/redhat/BUILD/da_exim-4.69/build-Linux-i386'
make: *** [go] Error 2
error: Bad exit status from /var/tmp/rpm-tmp.59032 (%build)


RPM build errors:
    Bad exit status from /var/tmp/rpm-tmp.59032 (%build)

libiconv.so and libiconv.so.2 are installed in my /usr/local/lib/ folder.
Also they have symlinks in /usr/lib/ folder.

I get the same error when compiling from source using this guide: http://help.directadmin.com/item.php?id=125

The OS is a fresh install, only directadmin/custombuild installed and restored users.
Specs: CentOS 5.2 / Apache 2.0.63 / PHP 5.2.8 / DirectAdmin 1.33 / Exim 4.67 / MySQL 5.0.67 / Named 9.3.4 / ProFTPd 1.3.2 / dovecot 1.1.11