Fix various internal #defines to conform to new C-language naming restrictions,
specifically that private-use macros names must not begin with "_".

FossilOrigin-Name: 5471aca0158851d3fb0a2517306917536deb38bb
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index c52cd29..998a17d 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -12,8 +12,8 @@
 ** Internal interface definitions for SQLite.
 **
 */
-#ifndef _SQLITEINT_H_
-#define _SQLITEINT_H_
+#ifndef SQLITEINT_H
+#define SQLITEINT_H
 
 /* Special Comments:
 **
@@ -4237,4 +4237,4 @@
 int sqlite3DbstatRegister(sqlite3*);
 #endif
 
-#endif /* _SQLITEINT_H_ */
+#endif /* SQLITEINT_H */