use c++ style references

Author: zimirza

libc/src/time/linux/localtime_utils.cpp

@@ -14,12 +14,12 @@
 namespace LIBC_NAMESPACE_DECL {
 namespace localtime_utils {
 
-void release_file(ErrorOr<File *> error_or_file) {
+void release_file(ErrorOr<File &> error_or_file) {
   file_usage = 0;
   error_or_file.value()->close();
 }
 
-ErrorOr<File *> acquire_file(char &filename) {
+ErrorOr<File &> acquire_file(char &filename) {
   while (1) {
     if (file_usage == 0) {
       file_usage = 1;

libc/src/time/time_utils.h

@@ -101,12 +101,12 @@ LIBC_INLINE tm *gmtime_internal(const time_t *timer, tm *result) {
 
 // TODO: localtime is not yet implemented and a temporary solution is to
 //       use gmtime, https://github.com/llvm/llvm-project/issues/107597
-LIBC_INLINE tm *localtime(const time_t *t_ptr) {
+LIBC_INLINE tm &localtime(const time_t &t_ptr) {
   static tm result;
   return time_utils::gmtime_internal(t_ptr, &result);
 }
 
-LIBC_INLINE struct tm *localtime_internal(const time_t &timer, struct tm &buf) {
+LIBC_INLINE struct tm &localtime_internal(const time_t &timer, struct tm &buf) {
   if (timer == nullptr) {
     invalid_value();
     return nullptr;