regcomp.c: Chg invlist_union() to accept NULL first param

It is common in a loop to keep adding inversion lists to a current
running total.  But the first time through, the current union list needs
to be initialized from NULL.  This puts that code in the function
instead of the callers each having to do it.

1 files changed, 1 insertions, 2 deletions

diff --git a/proto.h b/proto.h
index 6ac437a29e..6135af8330 100644
--- a/proto.h
+++ b/proto.h
@@ -6581,11 +6581,10 @@ PERL_CALLCONV void	Perl__invlist_subtract(pTHX_ SV* const a, SV* const b, SV** r
 	assert(a); assert(b); assert(result)
 
 PERL_CALLCONV void	Perl__invlist_union(pTHX_ SV* const a, SV* const b, SV** output)
-			__attribute__nonnull__(pTHX_1)
 			__attribute__nonnull__(pTHX_2)
 			__attribute__nonnull__(pTHX_3);
 #define PERL_ARGS_ASSERT__INVLIST_UNION	\
-	assert(a); assert(b); assert(output)
+	assert(b); assert(output)
 
 PERL_CALLCONV SV*	Perl__new_invlist(pTHX_ IV initial_size)
 			__attribute__warn_unused_result__;