diff --git a/src/Makefile.in b/src/Makefile.in
index ba539b07f90..4b6599dc26d 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -280,7 +280,7 @@ TOOLKIT_DEFINES =
 
 /* C_SWITCH_X_SITE must come before C_SWITCH_X_MACHINE and C_SWITCH_X_SYSTEM
    since it may have -I options that should override those two.  */
-ALL_CFLAGS=-Demacs -DHAVE_CONFIG_H $(TOOLKIT_DEFINES) $(MYCPPFLAGS) -I. -I${srcdir} C_SWITCH_MACHINE C_SWITCH_SYSTEM C_SWITCH_SITE C_SWITCH_X_SITE C_SWITCH_X_MACHINE C_SWITCH_X_SYSTEM C_SWITCH_SYSTEM_TEMACS ${CFLAGS}
+ALL_CFLAGS=-Demacs -DHAVE_CONFIG_H $(TOOLKIT_DEFINES) $(MYCPPFLAGS) -I. -I${srcdir} C_SWITCH_MACHINE C_SWITCH_SYSTEM C_SWITCH_SITE C_SWITCH_X_SITE C_SWITCH_X_MACHINE C_SWITCH_X_SYSTEM C_SWITCH_SYSTEM_TEMACS ${CFLAGS_SOUND} ${CFLAGS}
 .c.o:
 	$(CC) -c $(CPPFLAGS) $(ALL_CFLAGS) $<
 
@@ -453,6 +453,7 @@ LIBX= $(LIBXMENU) LD_SWITCH_X_SITE -lX10 LIBX10_MACHINE LIBX10_SYSTEM
 #endif /* not HAVE_X_WINDOWS */
 
 LIBSOUND= @LIBSOUND@
+CFLAGS_SOUND= @CFLAGS_SOUND@
 
 #ifndef ORDINARY_LINK
 /* Fix linking if compiled with GCC.  */