Make FreeBSD more flexible, don't look for jemalloc unless we were

given a specific path for it.

CMakeLists.txt

@@ -296,13 +296,19 @@ endif ()
 
 if (ENABLE_JEMALLOC)
     if (${CMAKE_SYSTEM_NAME} MATCHES "FreeBSD")
-        set(JEMALLOC_FOUND true)
-    else ()
-        find_package(JeMalloc)
-
-        if (NOT JEMALLOC_FOUND)
-            message(FATAL_ERROR "Could not find requested JeMalloc")
+        if (DEFINED ${JEMALLOC_ROOT_DIR})
+            # Look for jemalloc at a specific path
+            find_package(JeMalloc)
+        else()
+            # jemalloc is in the base system
+            set(JEMALLOC_FOUND true)
         endif()
+    else()
+        find_package(JeMalloc)
+    endif()
+
+    if (NOT JEMALLOC_FOUND)
+        message(FATAL_ERROR "Could not find requested JeMalloc")
     endif()
 endif ()