Bug: http://sourceforge.net/p/lame/bugs/443/
Bug-Debian: https://bugs.debian.org/760047

--- audacity-minsrc-2.4.2/lib-src/lame/libmp3lame/vector/Makefile.am.sse	2020-05-30 13:55:53.000000000 +0200
+++ audacity-minsrc-2.4.2/lib-src/lame/libmp3lame/vector/Makefile.am	2020-06-30 12:17:42.323878757 +0200
@@ -20,6 +20,7 @@ xmm_sources = xmm_quantize_sub.c
 
 if WITH_XMM
 liblamevectorroutines_la_SOURCES = $(xmm_sources)
+liblamevectorroutines_la_CFLAGS = -msse
 endif
 
 noinst_HEADERS = lame_intrin.h