Our HACKING discourages use of malloc and free, for at least
a couple of years now.  But we weren't enforcing it, until now :)

For now, I've exempted python and tests, and will clean those up
in subsequent patches.  Examples should be permanently exempt,
since anyone copying our examples won't have use of our
internal-only memory.h via libvirt_util.la.

* cfg.mk (sc_prohibit_raw_allocation): New rule.
(exclude_file_name_regexp--sc_prohibit_raw_allocation): and
exemptions.
* src/cpu/cpu.c (cpuDataFree): Avoid false positive.
* src/conf/network_conf.c (virNetworkDNSSrvDefParseXML): Fix
offenders.
* src/libxl/libxl_conf.c (libxlMakeDomBuildInfo, libxlMakeVfb)
(libxlMakeDeviceModelInfo): Likewise.
* src/rpc/virnetmessage.c (virNetMessageSaveError): Likewise.
* tools/virsh.c (_vshMalloc, _vshCalloc): Likewise.