Allow to enable ivsalloc independently
diff --git a/INSTALL b/INSTALL
index 9bd1dac..6e371ce 100644
--- a/INSTALL
+++ b/INSTALL
@@ -79,6 +79,12 @@
 --enable-debug
     Enable assertions and validation code.  This incurs a substantial
     performance hit, but is very useful during application development.
+    Implies --enable-ivsalloc.
+
+--enable-ivsalloc
+    Enable validation code, which verifies that pointers reside within
+    jemalloc-owned chunks before dereferencing them. This incurs a substantial
+    performance hit.
 
 --disable-stats
     Disable statistics gathering functionality.  See the "opt.stats_print"