diff --git a/changes/bug3909 b/changes/bug3909
new file mode 100644
index 0000000000..0b4b292030
--- /dev/null
+++ b/changes/bug3909
@@ -0,0 +1,3 @@
+  o Build fixes:
+    - Search for a platform-specific version of "ar" when cross-compiling.
+      Should fix builds on iOS. Found by Marco Bonetti.
diff --git a/configure.in b/configure.in
index f3640cb721..824547c6d7 100644
--- a/configure.in
+++ b/configure.in
@@ -148,6 +148,12 @@ fi
 AC_ARG_ENABLE(bufferevents,
      AS_HELP_STRING(--enable-bufferevents, use Libevent's buffered IO.))
 
+dnl check for the correct "ar" when cross-compiling
+AN_MAKEVAR([AR], [AC_PROG_AR])
+AN_PROGRAM([ar], [AC_PROG_AR])
+AC_DEFUN([AC_PROG_AR], [AC_CHECK_TOOL([AR], [ar], [ar])])
+AC_PROG_AR
+
 AC_PROG_CC
 AC_PROG_CPP
 AC_PROG_MAKE_SET