diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9a5d3047d3..98118f0090 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -90,21 +90,25 @@ if (NOT BINPAC_FOUND)
     endif ()
 endif ()
 
+set(HAVE_LIBMAGIC false)
 find_package(LibMagic)
 if (LIBMAGIC_FOUND)
     set(HAVE_LIBMAGIC true)
 endif ()
 
+set(HAVE_LIBZ false)
 find_package(ZLIB)
 if (ZLIB_FOUND)
     set(HAVE_LIBZ true)
 endif ()
 
+set(USE_GEOIP false)
 find_package(LibGeoIP)
 if (LIBGEOIP_FOUND)
     set(USE_GEOIP true)
 endif ()
 
+set(USE_PERFTOOLS false)
 if (ENABLE_PERFTOOLS)
     find_package(GooglePerftools)
     if (GOOGLEPERFTOOLS_FOUND)