[musl] [C23 new stdlib 2/4] C23: add the memalignment function

[Jens Gustedt <Jens.Gustedt@inria.fr>]

The name is reserved, so we don't need to protect it via a feature
macro or a weak symbol.
---
 include/stdlib.h          | 3 +++
 src/stdlib/memalignment.c | 6 ++++++
 2 files changed, 9 insertions(+)
 create mode 100644 src/stdlib/memalignment.c

diff --git a/include/stdlib.h b/include/stdlib.h
index 7800074d..68993c04 100644
--- a/include/stdlib.h
+++ b/include/stdlib.h
@@ -178,6 +178,9 @@ long double strtold_l(const char *__restrict, char **__restrict, struct __locale
 typedef int once_flag;
 void call_once(once_flag *, void (*)(void));
 
+size_t (memalignment)(const void *);
+#define memalignment(P) (((size_t)1)<<__builtin_ctzll((unsigned long long)P))
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/stdlib/memalignment.c b/src/stdlib/memalignment.c
new file mode 100644
index 00000000..58b68954
--- /dev/null
+++ b/src/stdlib/memalignment.c
@@ -0,0 +1,6 @@
+#include <stdlib.h>
+
+size_t (memalignment)(const void *p)
+{
+	return memalignment(p);
+}
-- 
2.34.1