diff --git a/Formula/cfitsio.rb b/Formula/cfitsio.rb
index bbf8c193f1..2af89d293a 100644
--- a/Formula/cfitsio.rb
+++ b/Formula/cfitsio.rb
@@ -13,8 +13,12 @@ class Cfitsio < Formula
     sha256 "7681f60baee8d9a73639be3f54d7f4a1c71c9fc9f4ac7fd0e3ba20cb2a2c3c7b" => :el_capitan
   end
 
+  option "with-reentrant", "Build with support for concurrency"
+
   def install
-    system "./configure", "--prefix=#{prefix}"
+    args = ["--prefix=#{prefix}"]
+    args << "--enable-reentrant" if build.with? "reentrant"
+    system "./configure", *args
     system "make", "shared"
     system "make", "install"
     (pkgshare/"testprog").install Dir["testprog*"]