https://sources.debian.org/src/enscript/1.6.5.90-3.2/debian/patches/1096582-gcc-15

--- a/compat/regex.c
+++ b/compat/regex.c
@@ -336,7 +336,10 @@ typedef char boolean;
 #define false 0
 #define true 1
 
-static int re_match_2_internal ();
+static int re_match_2_internal (struct re_pattern_buffer *bufp,
+	const char *string1, int size1,
+	const char *string2, int size2,
+	int pos, struct re_registers *regs, int stop);
 
 /* These are the command codes that appear in compiled regular
    expressions.  Some opcodes are followed by argument bytes.  A
