package/libargtable2: fix build error with gcc-14

The following build error is happening on the autobuilder:

```
arg_int.c:60:12: error: implicit declaration of function 'isspace' [-Wimplicit-function-declaration]
   60 |     while (isspace(*ptr))
      |            ^~~~~~~
arg_int.c:33:1: note: include '<ctype.h>' or provide a declaration of 'isspace'
   32 | #include <limits.h>
  +++ |+#include <ctype.h>
   33 |
arg_int.c:89:8: error: implicit declaration of function 'toupper' [-Wimplicit-function-declaration]
   89 |    if (toupper(*ptr++)!=toupper(X))
      |        ^~~~~~~
arg_int.c:89:8: note: include '<ctype.h>' or provide a declaration of 'toupper'
```

Both `isspace` and `toupper` are declared in the `ctype.h` header.
This build error started to happen with gcc-14.
The `ctype.h` include was added in a later upstream commit.
This patch adds that upstream commit and strip everything else to only
patch that include.

Fixes: https://autobuild.buildroot.org/results/d38/d38e3e12f52c3fde08ab446ca14a1a7bd65c9469//
Signed-off-by: Thomas Perale <thomas.perale@mind.be>
[Julien: add comment about gcc-14]
Signed-off-by: Julien Olivain <ju.o@free.fr>

package/libargtable2/0001-apply-uint-patch.patch

@@ -0,0 +1,25 @@
+From 3fe1ce4d7aa7c4fc16471a9ab023ecf6628c2f11 Mon Sep 17 00:00:00 2001
+From: Chris McClelland <prophet3636@gmail.com>
+Date: Thu, 12 Nov 2020 14:18:27 +0000
+Subject: [PATCH] Apply uint patch
+
+Upstream: https://github.com/makestuff/libargtable2/commit/3fe1ce4d7aa7c4fc16471a9ab023ecf6628c2f11
+[thomas: strip to only have the include]
+Signed-off-by: Thomas Perale <thomas.perale@mind.be>
+---
+ src/arg_int.c     |  2 ++
+ 1 files changed, 2 insertions(+)
+
+diff --git a/src/arg_int.c b/src/arg_int.c
+index 29c20e5..c51706a 100644
+--- a/src/arg_int.c
++++ b/src/arg_int.c
+@@ -24,6 +24,8 @@ USA.
+ #include "config.h"
+ #endif
+ 
++#include <ctype.h>
++
+ /* #ifdef HAVE_STDLIB_H */
+ #include <stdlib.h>
+ /* #endif */