Uses SNPRINT macro where possible. Otherwise uses #define for format.

runtime/vm/version_in.cc

Index: runtime/vm/version_in.cc
diff --git a/runtime/vm/version_in.cc b/runtime/vm/version_in.cc
index 34d7fc6763701db67c3e3ce3b5f0b7b443751623..c947c6d160082fa30013e2b8a670252b6a7843e8 100644
--- a/runtime/vm/version_in.cc
+++ b/runtime/vm/version_in.cc
@@ -14,13 +14,11 @@ static const char* formatted_version = NULL;
 
 const char* Version::String() {
   if (formatted_version == NULL) {
-    const char* format = "%s on \"%s_%s\"";
     const char* os = OS::Name();
     const char* arch = CPU::Id();
 
-    intptr_t len = OS::SNPrint(NULL, 0, format, str_, os, arch);
-    char* buffer = reinterpret_cast<char*>(malloc(len + 1));
-    OS::SNPrint(buffer, (len + 1), format, str_, os, arch);
+    char* buffer = NULL;
+    SNPRINT(buffer, malloc, "%s on \"%s_%s\"", str_, os, arch);
     formatted_version = buffer;
   }
   return formatted_version;