Make "kernaux_memset" signature compatible with C stdlib "memset"

include/kernaux/stdlib.h

@@ -1,15 +1,13 @@
 #ifndef KERNAUX_INCLUDED_STDLIB
 #define KERNAUX_INCLUDED_STDLIB 1
 
+#include <stddef.h>
+
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-void kernaux_memset(
-    void *buffer,
-    unsigned char value,
-    unsigned long size
-)
+void *kernaux_memset(void *buffer, int value, size_t size)
 __attribute__((nonnull));
 
 unsigned int kernaux_strlen(const char *s) __attribute__((nonnull));

src/stdlib.c

@@ -4,16 +4,15 @@
 
 #include <kernaux/stdlib.h>
 
-void kernaux_memset(
-    void *const buffer,
-    const unsigned char value,
-    const unsigned long size
-) {
+void *kernaux_memset(void *const buffer, const int value, const size_t size)
+{
     unsigned char *const s = buffer;
 
     for (unsigned long i = 0; i < size; ++i) {
         s[i] = value;
     }
+
+    return buffer;
 }
 
 unsigned int kernaux_strlen(const char *const s)

tests/test_stdlib.c

@@ -14,7 +14,7 @@ int main()
         unsigned char buffer[10] =
             {32, 13, 254, 165, 98, 36, 169, 152, 233, 222};
 
-        kernaux_memset(buffer, 0, sizeof(buffer));
+        assert(kernaux_memset(buffer, 0, sizeof(buffer)) == buffer);
 
         for (unsigned int i = 0; i < sizeof(buffer); ++i) {
             assert(buffer[i] == 0);
@@ -25,13 +25,24 @@ int main()
         unsigned char buffer[10] =
             {32, 13, 254, 165, 98, 36, 169, 152, 233, 222};
 
-        kernaux_memset(buffer, 143, sizeof(buffer));
+        assert(kernaux_memset(buffer, 143, sizeof(buffer)) == buffer);
 
         for (unsigned int i = 0; i < sizeof(buffer); ++i) {
             assert(buffer[i] == 143);
         }
     }
 
+    {
+        unsigned char buffer[10] =
+            {32, 13, 254, 165, 98, 36, 169, 152, 233, 222};
+
+        assert(kernaux_memset(buffer, 0x89ABCDEF, sizeof(buffer)) == buffer);
+
+        for (unsigned int i = 0; i < sizeof(buffer); ++i) {
+            assert(buffer[i] == 0xEF);
+        }
+    }
+
     // kernaux_strlen
 
     assert(kernaux_strlen("") == 0);