os: make minior improvement to C function semantics and related code (#…

…21565)

vlib/os/os_nix.c.v

@@ -61,9 +61,9 @@ pub const s_iwoth = 0o0002 // Write by others
 
 pub const s_ixoth = 0o0001
 
-fn C.utime(&char, voidptr) int
+fn C.utime(&char, &C.utimbuf) int
 
-fn C.uname(name voidptr) int
+fn C.uname(name &C.utsname) int
 
 fn C.symlink(&char, &char) int
 
@@ -215,7 +215,7 @@ fn native_glob_pattern(pattern string, mut matches []string) ! {
 
 pub fn utime(path string, actime int, modtime int) ! {
 	u := C.utimbuf{actime, modtime}
-	if C.utime(&char(path.str), voidptr(&u)) != 0 {
+	if C.utime(&char(path.str), &u) != 0 {
 		return error_with_code(posix_get_error_msg(C.errno), C.errno)
 	}
 }
@@ -238,10 +238,8 @@ pub fn utime(path string, actime int, modtime int) ! {
 // See also https://pubs.opengroup.org/onlinepubs/7908799/xsh/sysutsname.h.html
 pub fn uname() Uname {
 	mut u := Uname{}
-	utsize := sizeof(C.utsname)
 	unsafe {
-		x := malloc_noscan(int(utsize))
-		d := &C.utsname(x)
+		d := &C.utsname(malloc_noscan(int(sizeof(C.utsname))))
 		if C.uname(d) == 0 {
 			u.sysname = cstring_to_vstring(d.sysname)
 			u.nodename = cstring_to_vstring(d.nodename)