Compilation of src/XCCDF/result.c fails on some platforms

[Jan Lána]

Description of Problem:

Compilation of result.c on Solaris OS failed because undefined structures:

...
openscap/openscap-1.3.7/src/XCCDF/result.c: In function 'xccdf_result_fill_sysinfo':
openscap/openscap-1.3.7/src/XCCDF/result.c:323:41: error: storage size of 'hints' isn't known
  323 |                         struct addrinfo hints, *info, *p;                 
...

It is because netdb.h is include only if OS_LINUX or OS_FREEBSD is defined. But according the RFC3493 the netdb.h should be included on all UNIX systems.

Operating System & Version:

Solaris OS, but IMHO it affects all unix systems except Linux and FreeBSD-like

Steps to Reproduce:

cmake && make

Actual Results:

...
[ 57%] Building C object src/XCCDF/CMakeFiles/xccdf_object.dir/result.c.o
/builds/openscap/openscap-1.3.7/src/XCCDF/result.c: In function 'xccdf_result_fill_sysinfo':
/builds/openscap/openscap-1.3.7/src/XCCDF/result.c:323:41: error: storage size of 'hints' isn't known
  323 |                         struct addrinfo hints, *info, *p;
      |                                         ^~~~~
/builds/openscap/openscap-1.3.7/src/XCCDF/result.c:329:42: error: 'AI_CANONNAME' undeclared (first use in this function)
  329 |                         hints.ai_flags = AI_CANONNAME;
      |                                          ^~~~~~~~~~~~
/builds/openscap/openscap-1.3.7/src/XCCDF/result.c:329:42: note: each undeclared identifier is reported only once for each function it appears in
/builds/openscap/openscap-1.3.7/src/XCCDF/result.c:331:41: warning: implicit declaration of function 'getaddrinfo' [-Wimplicit-function-declaration]
  331 |                         if (!(gai_res = getaddrinfo(hostname, NULL, &hints, &info))) {
      |                                         ^~~~~~~~~~~
/builds/openscap/openscap-1.3.7/src/XCCDF/result.c:332:63: error: invalid use of undefined type 'struct addrinfo'
  332 |                                 for(p = info; p != NULL; p = p->ai_next) {
      |                                                               ^~
/builds/openscap/openscap-1.3.7/src/XCCDF/result.c:333:47: error: invalid use of undefined type 'struct addrinfo'
  333 |                                         if (!p->ai_canonname)
      |                                               ^~
/builds/openscap/openscap-1.3.7/src/XCCDF/result.c:337:77: error: invalid use of undefined type 'struct addrinfo'
  337 |                                         xccdf_target_fact_set_string(fact, p->ai_canonname);
      |                                                                             ^~
/builds/openscap/openscap-1.3.7/src/XCCDF/result.c:341:64: error: invalid use of undefined type 'struct addrinfo'
  341 |                                                 fqdn = strdup(p->ai_canonname);
      |                                                                ^~
/builds/openscap/openscap-1.3.7/src/XCCDF/result.c:343:33: warning: implicit declaration of function 'freeaddrinfo' [-Wimplicit-function-declaration]
  343 |                                 freeaddrinfo(info);
      |                                 ^~~~~~~~~~~~
...