[Buildroot] [PATCH v4] package/which: fix getopt prototype for GCC 15

* [Buildroot] [PATCH v4] package/which: fix getopt prototype for GCC 15
@ 2026-03-11  9:27 Shubham Chakraborty
  2026-05-31  6:09 ` Thomas Petazzoni via buildroot
  0 siblings, 1 reply; 3+ messages in thread
From: Shubham Chakraborty @ 2026-03-11  9:27 UTC (permalink / raw)
  To: buildroot; +Cc: thomas.petazzoni, Shubham Chakraborty

Older C standards allowed empty parentheses in function declarations,
but GCC 15 enforces C23 semantics where extern int getopt() is
equivalent to extern int getopt(void), which conflicts with the
typed prototype provided by system headers (e.g. musl's unistd.h).

Fix by providing the full prototype in the non-GNU fallback branch,
matching the standard getopt() signature.

Signed-off-by: Shubham Chakraborty <chakrabortyshubham66@gmail.com>
---
Changes v3 -> v4:
 - Fixed patch submission: now correctly adds patch file as new file
   instead of showing modifications to existing patch file
 - Improved commit message clarity

Changes v2 -> v3:
 - Added proper patch header with description and Signed-off-by
 - Identified GCC 15 (not musl) as root cause

Changes v1 -> v2:
 - Fixed commit message format

Apologies for the confusion in v3 - still learning the patch submission
process. This version should be correct.
---
 ...hich-fix-getopt-prototype-for-GCC-15.patch | 34 +++++++++++++++++++
 1 file changed, 34 insertions(+)
 create mode 100644 package/which/0001-package-which-fix-getopt-prototype-for-GCC-15.patch

diff --git a/package/which/0001-package-which-fix-getopt-prototype-for-GCC-15.patch b/package/which/0001-package-which-fix-getopt-prototype-for-GCC-15.patch
new file mode 100644
index 0000000000..afae321ce7
--- /dev/null
+++ b/package/which/0001-package-which-fix-getopt-prototype-for-GCC-15.patch
@@ -0,0 +1,34 @@
+From f1d07e5630628a7d218936b3ac3292daf6a7ba77 Mon Sep 17 00:00:00 2001
+From: Shubham Chakraborty <chakrabortyshubham66@gmail.com>
+Date: Mon, 9 Mar 2026 21:43:58 +0530
+Subject: [PATCH] package/which: fix getopt prototype for GCC 15
+
+Older C standards allowed empty parentheses in function declarations,
+but GCC 15 enforces C23 semantics where extern int getopt() is
+equivalent to extern int getopt(void), which conflicts with the
+typed prototype provided by system headers (e.g. musl's unistd.h).
+
+Fix by providing the full prototype in the non-GNU fallback branch,
+matching the standard getopt() signature.
+
+Signed-off-by: Shubham Chakraborty <chakrabortyshubham66@gmail.com>
+---
+ getopt.h | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/getopt.h b/getopt.h
+index f080053..081334f 100644
+--- a/getopt.h
++++ b/getopt.h
+@@ -102,7 +102,7 @@ struct option {
+    errors, only prototype getopt for the GNU C library.  */
+ extern int getopt(int argc, char *const *argv, const char *shortopts);
+ #else  /* not __GNU_LIBRARY__ */
+-extern int getopt();
++extern int getopt(int argc, char *const *argv, const char *shortopts);
+ #endif /* __GNU_LIBRARY__ */
+ extern int getopt_long(int argc, char *const *argv, const char *shortopts, const struct option *longopts, int *longind);
+ extern int getopt_long_only(int argc, char *const *argv, const char *shortopts, const struct option *longopts,
+-- 
+2.53.0
+
-- 
2.53.0

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