diff --git a/MozillaFirefox.changes b/MozillaFirefox.changes
index a2948ce..bbfaf95 100644
--- a/MozillaFirefox.changes
+++ b/MozillaFirefox.changes
@@ -2,6 +2,7 @@
 Mon Mar 20 15:35:57 UTC 2017 - wr@rosenauer.org
 
 - disable rust usage for everything but x86(-64)
+- explicitely add libffi build requirement
 
 -------------------------------------------------------------------
 Fri Mar 17 15:43:29 UTC 2017 - wr@rosenauer.org
diff --git a/MozillaFirefox.spec b/MozillaFirefox.spec
index f2ecf61..1127394 100644
--- a/MozillaFirefox.spec
+++ b/MozillaFirefox.spec
@@ -91,6 +91,7 @@ BuildRequires:  update-desktop-files
 BuildRequires:  xorg-x11-libXt-devel
 BuildRequires:  yasm
 BuildRequires:  zip
+BuildRequires:  pkgconfig(libffi)
 BuildRequires:  pkgconfig(libpulse)
 %if 0%{?firefox_use_gtk3}
 BuildRequires:  pkgconfig(glib-2.0)