clamav: allow configuration to use TCP socket

Something having to do with passing a file descriptor over spamd's
Unix socket causes the ClamAV milter to fail. The milter says "ERROR:
Unknown reply from clamd," and running strace on spamd reveals "No file
descriptor received. ERROR."

Some work by others can be found on the Internet that suggests using
a TCP socket for the communication between the milter and spamd fixes
this. Lucian Cristian confirmed this on OpenWrt.

I am not sure why the Unix socket does not work. I suspect it is something
related to musl, but I have not yet found evidence of this.

This merge request adds the option to configure spamd to use a TCP
socket, and it uses this as the default. The merge request also adds an
init script for clamav-milter.

Signed-off-by: W. Michael Petullo <mike@flyn.org>

net/clamav/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=clamav
 PKG_VERSION:=0.102.4
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
 PKG_SOURCE_URL:=https://www.clamav.net/downloads/production/
@@ -88,6 +88,7 @@ TARGET_LDFLAGS += -Wl,--gc-sections,--as-needed $(if $(CONFIG_USE_MUSL),-lfts)
 
 define Package/clamav/conffiles
 /etc/config/clamav
+/etc/config/clamav-milter
 endef
 
 define Package/clamav/install
@@ -106,9 +107,11 @@ define Package/clamav/install
 
 	$(INSTALL_DIR) $(1)/etc/config
 	$(INSTALL_CONF) ./files/clamav.config $(1)/etc/config/clamav
+	$(INSTALL_CONF) ./files/clamav-milter.config $(1)/etc/config/clamav-milter
 
 	$(INSTALL_DIR) $(1)/etc/init.d/
 	$(INSTALL_BIN) ./files/clamav.init $(1)/etc/init.d/clamav
+	$(INSTALL_BIN) ./files/clamav-milter.init $(1)/etc/init.d/clamav-milter
 
 	$(INSTALL_DIR) $(1)/usr/share/clamav
 	$(CP) ./files/bytecode.cvd $(1)/usr/share/clamav/