--- a/js/src/old-configure.in
+++ b/js/src/old-configure.in
@@ -2018,18 +2018,18 @@ OS_CXXFLAGS="$CXXFLAGS"
 OS_CPPFLAGS="$CPPFLAGS"
 OS_COMPILE_CFLAGS="$COMPILE_CFLAGS"
 OS_COMPILE_CXXFLAGS="$COMPILE_CXXFLAGS"
 OS_LDFLAGS="$LDFLAGS"
 OS_LIBS="$LIBS"
 AC_SUBST(OS_CFLAGS)
 AC_SUBST(OS_CXXFLAGS)
 AC_SUBST(OS_CPPFLAGS)
-AC_SUBST(OS_COMPILE_CFLAGS)
-AC_SUBST(OS_COMPILE_CXXFLAGS)
+AC_SUBST_LIST(OS_COMPILE_CFLAGS)
+AC_SUBST_LIST(OS_COMPILE_CXXFLAGS)
 AC_SUBST(OS_LDFLAGS)
 AC_SUBST(OS_LIBS)
 
 AC_SUBST(HOST_CC)
 AC_SUBST(HOST_CXX)
 AC_SUBST(HOST_CFLAGS)
 AC_SUBST(HOST_CPPFLAGS)
 AC_SUBST(HOST_CXXFLAGS)

--- a/old-configure.in
+++ b/old-configure.in
@@ -4812,18 +4812,18 @@ OS_CXXFLAGS="$CXXFLAGS"
 OS_CPPFLAGS="$CPPFLAGS"
 OS_COMPILE_CFLAGS="$COMPILE_CFLAGS"
 OS_COMPILE_CXXFLAGS="$COMPILE_CXXFLAGS"
 OS_LDFLAGS="$LDFLAGS"
 OS_LIBS="$LIBS"
 AC_SUBST(OS_CFLAGS)
 AC_SUBST(OS_CXXFLAGS)
 AC_SUBST(OS_CPPFLAGS)
-AC_SUBST(OS_COMPILE_CFLAGS)
-AC_SUBST(OS_COMPILE_CXXFLAGS)
+AC_SUBST_LIST(OS_COMPILE_CFLAGS)
+AC_SUBST_LIST(OS_COMPILE_CXXFLAGS)
 AC_SUBST(OS_LDFLAGS)
 AC_SUBST(OS_LIBS)
 
 AC_SUBST(HOST_CC)
 AC_SUBST(HOST_CXX)
 AC_SUBST(HOST_CFLAGS)
 AC_SUBST(HOST_CPPFLAGS)
 AC_SUBST(HOST_CXXFLAGS)