Remove automagic dependency on SNMP. Gentoo bug 911114.
https://bugs.gentoo.org/911114

--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -145,6 +145,10 @@
   set (OPENVAS_RUN_DIR "/run/ospd")
 endif (NOT OPENVAS_RUN_DIR)

+if (NOT BUILD_WITH_SNMP)
+  set (BUILD_WITH_SNMP "TRUE")
+endif (NOT BUILD_WITH_SNMP)
+
 set (OPENVAS_DATA_DIR    "${DATADIR}/openvas")
 set (OPENVAS_STATE_DIR   "${LOCALSTATEDIR}/lib/openvas")

--- a/nasl/CMakeLists.txt
+++ b/nasl/CMakeLists.txt
@@ -70,14 +70,16 @@
     OUTPUT_STRIP_TRAILING_WHITESPACE)
 endif (NOT GPGME_FOUND)

-message (STATUS "Looking for netsnmp...")
-find_library (SNMP netsnmp)
-message (STATUS "Looking for netsnmp... ${SNMP}")
-if (SNMP)
-  execute_process (COMMAND net-snmp-config --libs
-    OUTPUT_VARIABLE SNMP_LDFLAGS
-    OUTPUT_STRIP_TRAILING_WHITESPACE)
-endif (SNMP)
+if (BUILD_WITH_SNMP)
+  message (STATUS "Looking for netsnmp...")
+  find_library (SNMP netsnmp)
+  message (STATUS "Looking for netsnmp... ${SNMP}")
+  if (SNMP)
+    execute_process (COMMAND net-snmp-config --libs
+      OUTPUT_VARIABLE SNMP_LDFLAGS
+      OUTPUT_STRIP_TRAILING_WHITESPACE)
+  endif (SNMP)
+endif (BUILD_WITH_SNMP)

 message (STATUS "Looking for libgcrypt...")
 find_library (GCRYPT gcrypt)