Replace old-style cast of null pointer with nullptr

Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: d42baff45d9700a199982ba0ac04dbc6c6d911bb
diff --git a/src/locale.cpp b/src/locale.cpp
index 2757eaa..b918088 100644
--- a/src/locale.cpp
+++ b/src/locale.cpp
@@ -536,7 +536,7 @@
 
 locale::locale(const char* name)
     : __locale_(name ? new __imp(name)
-                     : (__throw_runtime_error("locale constructed with null"), (__imp*)0))
+                     : (__throw_runtime_error("locale constructed with null"), nullptr))
 {
     __locale_->__add_shared();
 }
@@ -549,7 +549,7 @@
 
 locale::locale(const locale& other, const char* name, category c)
     : __locale_(name ? new __imp(*other.__locale_, name, c)
-                     : (__throw_runtime_error("locale constructed with null"), (__imp*)0))
+                     : (__throw_runtime_error("locale constructed with null"), nullptr))
 {
     __locale_->__add_shared();
 }