--- /usr/portage/media-libs/libwebp/libwebp-0.5.1.ebuild	2016-08-17 00:06:03.000000000 +0200
+++ libwebp-0.5.1.ebuild	2016-11-02 17:31:49.136719485 +0100
@@ -12,7 +12,7 @@
 LICENSE="BSD"
 SLOT="0/6" # subslot = libwebp soname version
 KEYWORDS="~alpha ~amd64 ~arm ~arm64 ~hppa ~ia64 ~mips ~ppc ~ppc64 ~s390 ~sparc ~x86 ~amd64-fbsd ~x86-fbsd ~amd64-linux ~x86-linux ~x64-macos ~m68k-mint"
-IUSE="experimental gif +jpeg opengl +png static-libs swap-16bit-csp tiff"
+IUSE="cpu_flags_x86_sse2 cpu_flags_x86_sse4_1 experimental gif +jpeg opengl +png static-libs swap-16bit-csp tiff"
 
 # TODO: dev-lang/swig bindings in swig/ subdirectory
 RDEPEND="gif? ( media-libs/giflib:= )
@@ -52,6 +52,14 @@
 		$(multilib_native_use_enable gif)
 	)
 
+	if ! use cpu_flags_x86_sse2; then
+		args+=('--disable-sse2')
+	fi
+	
+	if ! use cpu_flags_x86_sse4_1; then
+		args+=('--disable-sse4.1')
+	fi
+
 	econf "${args[@]}"
 }