package/unifdef: fix build with gcc 15

Add a patch fixing compilation on hosts with gcc 15.

Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
Signed-off-by: Julien Olivain <ju.o@free.fr>
(cherry picked from commit 22cd2e0bc4545d46d92936e5bb5c98f1e22d58f8)
Signed-off-by: Thomas Perale <thomas.perale@mind.be>

package/unifdef/0002-Don-t-use-C23-constexpr-keyword.patch

@@ -0,0 +1,60 @@
+From d616741e6b0d5b57b66447e85ad32b283b28adde Mon Sep 17 00:00:00 2001
+From: Sam James <sam@gentoo.org>
+Date: Sun, 17 Nov 2024 01:26:27 +0000
+Subject: [PATCH] Don't use C23 constexpr keyword
+
+This fixes building with upcoming GCC 15 which defaults to -std=gnu23.
+
+Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
+Upstream: https://github.com/fanf2/unifdef/pull/19
+---
+ unifdef.c | 10 +++++-----
+ 1 file changed, 5 insertions(+), 5 deletions(-)
+
+diff --git a/unifdef.c b/unifdef.c
+index dc145a2..4bd3bda 100644
+--- a/unifdef.c
++++ b/unifdef.c
+@@ -202,7 +202,7 @@ static int              depth;			/* current #if nesting */
+ static int              delcount;		/* count of deleted lines */
+ static unsigned         blankcount;		/* count of blank lines */
+ static unsigned         blankmax;		/* maximum recent blankcount */
+-static bool             constexpr;		/* constant #if expression */
++static bool             is_constexpr;		/* constant #if expression */
+ static bool             zerosyms;		/* to format symdepth output */
+ static bool             firstsym;		/* ditto */
+ 
+@@ -1086,7 +1086,7 @@ eval_unary(const struct ops *ops, long *valp, const char **cpp)
+ 			*valp = (value[sym] != NULL);
+ 			lt = *valp ? LT_TRUE : LT_FALSE;
+ 		}
+-		constexpr = false;
++		is_constexpr = false;
+ 	} else if (!endsym(*cp)) {
+ 		debug("eval%d symbol", prec(ops));
+ 		sym = findsym(&cp);
+@@ -1103,7 +1103,7 @@ eval_unary(const struct ops *ops, long *valp, const char **cpp)
+ 			lt = *valp ? LT_TRUE : LT_FALSE;
+ 			cp = skipargs(cp);
+ 		}
+-		constexpr = false;
++		is_constexpr = false;
+ 	} else {
+ 		debug("eval%d bad expr", prec(ops));
+ 		return (LT_ERROR);
+@@ -1170,10 +1170,10 @@ ifeval(const char **cpp)
+ 	long val = 0;
+ 
+ 	debug("eval %s", *cpp);
+-	constexpr = killconsts ? false : true;
++	is_constexpr = killconsts ? false : true;
+ 	ret = eval_table(eval_ops, &val, cpp);
+ 	debug("eval = %d", val);
+-	return (constexpr ? LT_IF : ret == LT_ERROR ? LT_IF : ret);
++	return (is_constexpr ? LT_IF : ret == LT_ERROR ? LT_IF : ret);
+ }
+ 
+ /*
+-- 
+2.34.1
+