sprintf -> PyOS_snprintf in some "obviously safe" cases.
Also changed <>-style #includes to ""-style in some places where the
former didn't make sense.
diff --git a/Modules/pyexpat.c b/Modules/pyexpat.c
index dada234..90e53b6 100644
--- a/Modules/pyexpat.c
+++ b/Modules/pyexpat.c
@@ -129,7 +129,7 @@
     int column = XML_GetErrorColumnNumber(parser);
     enum XML_Error code = XML_GetErrorCode(parser);
 
-    sprintf(buffer, "%.200s: line %i, column %i",
+    PyOS_snprintf(buffer, sizeof(buffer), "%.200s: line %i, column %i",
             XML_ErrorString(code), lineno, column);
     err = PyObject_CallFunction(ErrorObject, "s", buffer);
     if (  err != NULL