+Patch to allow building libffi using clang:
+ https://github.com/libffi/libffi/issues/191
+
+Can be dropped after the next libffi release.
+
+diff -u -r ../libffi-3.2.1/src/arm/sysv.S ./src/arm/sysv.S
+--- ../libffi-3.2.1/src/arm/sysv.S 2014-11-08 07:47:24.000000000 -0500
++++ ./src/arm/sysv.S 2016-05-16 20:37:25.684302345 -0400
+@@ -396,7 +396,7 @@
+ beq LSYM(Lepilogue_vfp)
+
+ cmp r3, #FFI_TYPE_SINT64
+- stmeqia r2, {r0, r1}
++ stmiaeq r2, {r0, r1}
+ beq LSYM(Lepilogue_vfp)
+
+ cmp r3, #FFI_TYPE_FLOAT