vpx: properly quote VPX_LDFLAGS

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>
(cherry picked from commit 7a291b65d38daccdbabe55c3d3dcb1b3c2375222)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

contrib/src/vpx/rules.mak

@@ -102,7 +102,7 @@ VPX_CONF += --extra-cflags="-I $(ANDROID_NDK)/sources/cpufeatures/"
 endif
 
 .vpx: libvpx
-	cd $< && LDFLAGS=$(VPX_LDFLAGS) CROSS=$(VPX_CROSS) ./configure --target=$(VPX_TARGET) \
+	cd $< && LDFLAGS="$(VPX_LDFLAGS)" CROSS=$(VPX_CROSS) ./configure --target=$(VPX_TARGET) \
 		$(VPX_CONF) --prefix=$(PREFIX)
 	cd $< && $(MAKE)
 	cd $< && ../../../contrib/src/pkg-static.sh vpx.pc