[Buildroot] [git commit branch/2021.08.x] support/kconfig: fix compiler warnings

commit: https://git.buildroot.net/buildroot/commit/?id=427c299a843aef84e11ca5dc64e9235f8d1428dd
branch: https://git.buildroot.net/buildroot/commit/?id=refs/heads/2021.08.x

Compiling on Ubuntu 20.04 generates this:

./util.c: In function ���file_write_dep���
./util.c:54:18: warning: ���..config.tmp��� directive writing 12 bytes into a region of size between 1 and 4097 [-Wformat-overflow=]
   54 |  sprintf(buf, "%s..config.tmp", dir);
      |                  ^~~~~~~~~~~~
./util.c:54:2: note: ���sprintf��� output between 13 and 4109 bytes into a destination of size 4097
   54 |  sprintf(buf, "%s..config.tmp", dir);
      |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

and similar warnings on confdata.c, lines 778, 989, 995, 1000, 1007,
1040, 1046 and 1054. Avoid the warnings by enlarging the destination
buffer of fprintf().

Normally, we want changes to kconfig to be reflected by patches in
support/kconfig/patches. This makes it easier to resync with upstream
kconfig. However, in this case, everything that is changed here is
already changed completely (and differently) upstream, so there is no
added value in keeping the patch.

Signed-off-by: Edgar Bonet <redacted>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <redacted>
(cherry picked from commit 324612d68e09d0db44c51c451bc6b87466f7f874)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
---
 support/kconfig/confdata.c | 4 ++--
 support/kconfig/util.c     | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/support/kconfig/confdata.c b/support/kconfig/confdata.c
index 892da74fdc..9ab980edd8 100644
--- a/support/kconfig/confdata.c
+++ b/support/kconfig/confdata.c

@@ -744,7 +744,7 @@ int conf_write(const char *name)
 	struct menu *menu;
 	const char *basename;
 	const char *str;
-	char dirname[PATH_MAX+1], tmpname[PATH_MAX+1], newname[PATH_MAX+1];
+	char dirname[PATH_MAX+1], tmpname[PATH_MAX+20], newname[PATH_MAX+1];
 	char *env;
 
 	if (!name)

@@ -974,7 +974,7 @@ int conf_write_autoconf(void)
 	const char *name;
 	FILE *out, *tristate, *out_h;
 	int i;
-	char dir[PATH_MAX+1], buf[PATH_MAX+1];
+	char dir[PATH_MAX+1], buf[PATH_MAX+20];
 	char *s;
 
 	strcpy(dir, conf_get_configname());

diff --git a/support/kconfig/util.c b/support/kconfig/util.c
index 18a8e52391..8665f5bb89 100644
--- a/support/kconfig/util.c
+++ b/support/kconfig/util.c

@@ -35,7 +35,7 @@ struct file *file_lookup(const char *name)
 int file_write_dep(const char *name)
 {
 	char *str;
-	char buf[PATH_MAX+1], buf2[PATH_MAX+1], dir[PATH_MAX+1];
+	char buf[PATH_MAX+20], buf2[PATH_MAX+1], dir[PATH_MAX+1];
 	struct symbol *sym, *env_sym;
 	struct expr *e;
 	struct file *file;