Cannot compile agent on Solaris 8:

$ uname -X
System = SunOS
Release = 5.8
KernelID = Generic_108528-29
Machine = sun4u

$ make
Making all in src
Making all in libs
Making all in zbxcrypto
Making all in zbxcommon
Making all in zbxlog
Making all in zbxalgo
Making all in zbxnix
Making all in zbxconf
Making all in zbxsysinfo
Making all in common
gcc -DHAVE_CONFIG_H -I. -I../../../../include -g -O2 -MT net.o -MD -MP -MF .deps/net.Tpo -c -o net.o net.c
net.c: In function `CHECK_DNS':
net.c:337: error: `_res' undeclared (first use in this function)
net.c:337: error: (Each undeclared identifier is reported only once
net.c:337: error: for each function it appears in.)
net.c:337: error: `RES_INIT' undeclared (first use in this function)

• • • Error code 1
      make: Fatal error: Command failed for target `net.o'