[libc][NFC] replace NULL with nullptr (llvm#134464)

Simple cleanup

Author: michaelrj-google

libc/src/sys/time/linux/utimes.cpp

@@ -30,11 +30,11 @@ LLVM_LIBC_FUNCTION(int, utimes,
 #elif defined(SYS_utimensat)
   // the utimensat syscall requires a timespec struct, not timeval.
   struct timespec ts[2];
-  struct timespec *ts_ptr = nullptr; // default value if times is NULL
+  struct timespec *ts_ptr = nullptr; // default value if times is nullptr
 
   // convert the microsec values in timeval struct times
   // to nanosecond values in timespec struct ts
-  if (times != NULL) {
+  if (times != nullptr) {
 
     // ensure consistent values
     if ((times[0].tv_usec < 0 || times[1].tv_usec < 0) ||
@@ -54,7 +54,7 @@ LLVM_LIBC_FUNCTION(int, utimes,
     ts_ptr = ts;
   }
 
-  // If times was NULL, ts_ptr remains NULL, which utimensat interprets
+  // If times was nullptr, ts_ptr remains nullptr, which utimensat interprets
   // as setting times to the current time.
 
   // utimensat syscall.

libc/test/src/time/ctime_test.cpp

@@ -11,10 +11,10 @@
 #include "test/UnitTest/Test.h"
 #include "test/src/time/TmHelper.h"
 
-TEST(LlvmLibcCtime, NULL) {
+TEST(LlvmLibcCtime, nullptr) {
   char *result;
-  result = LIBC_NAMESPACE::ctime(NULL);
-  ASSERT_STREQ(NULL, result);
+  result = LIBC_NAMESPACE::ctime(nullptr);
+  ASSERT_STREQ(nullptr, result);
 }
 
 TEST(LlvmLibcCtime, ValidUnixTimestamp0) {
@@ -38,5 +38,5 @@ TEST(LlvmLibcCtime, InvalidArgument) {
   char *result;
   t = 2147483648;
   result = LIBC_NAMESPACE::ctime(&t);
-  ASSERT_STREQ(NULL, result);
+  ASSERT_STREQ(nullptr, result);
 }