diff --git a/firefox.spec b/firefox.spec
index a55747f..89f02ba 100644
--- a/firefox.spec
+++ b/firefox.spec
@@ -205,6 +205,7 @@ BuildRequires:  pkgconfig(libpulse)
 BuildRequires:  pkgconfig(icu-i18n)
 BuildRequires:  pkgconfig(gconf-2.0)
 BuildRequires:  yasm
+BuildRequires:  llvm-devel
 
 Requires:       mozilla-filesystem
 Requires:       p11-kit-trust