diff --git a/ChangeLog.txt b/ChangeLog.txt
index 67412362..423a82ea 100644
--- a/ChangeLog.txt
+++ b/ChangeLog.txt
@@ -1,3 +1,9 @@
+Significant changes since 0.0.91
+================================
+
+[1] Fixed x86-64 build on FreeBSD systems
+
+
 Significant changes since 0.0.90
 ================================
 
diff --git a/acinclude.m4 b/acinclude.m4
index b8254b65..570e606c 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -44,7 +44,14 @@ case "$host_os" in
     if echo __ELF__ | $CC -E - | grep __ELF__ > /dev/null; then
       objfmt='BSD-a.out'
     else
-      objfmt='ELF'
+      case "$host_cpu" in
+        x86_64)
+          objfmt='ELF64'
+          ;;
+        *)
+          objfmt='ELF'
+          ;;
+      esac
     fi
   ;;
   solaris* | sunos* | sysv* | sco*)