diff --git a/apps/progs.h b/apps/progs.h
index ac12d4fc413369d7a3fc0d2118746cc2209aa106..216c9d9f2a6c644d5db6c8ae708a01fbb862b715 100644
--- a/apps/progs.h
+++ b/apps/progs.h
@@ -1,3 +1,5 @@
+/* This file was generated by progs.pl. */
+
 #ifndef NOPROTO
 extern int verify_main(int argc,char *argv[]);
 extern int asn1parse_main(int argc,char *argv[]);
@@ -56,7 +58,7 @@ extern int nseq_main();
 extern int pkcs12_main();
 #endif
 
-#ifdef SSLEAY_SRC
+#ifdef SSLEAY_SRC  /* Defined only in openssl.c. */
 
 #define FUNC_TYPE_GENERAL	1
 #define FUNC_TYPE_MD		2
diff --git a/apps/progs.pl b/apps/progs.pl
index dfa308c5adde992613bb0316ea437a39313d03e5..34dcac16813c26d462ef8a552b1167c1ba02ac77 100644
--- a/apps/progs.pl
+++ b/apps/progs.pl
@@ -1,5 +1,7 @@
 #!/usr/local/bin/perl
 
+print "/* This file was generated by progs.pl. */\n\n";
+
 print "#ifndef NOPROTO\n";
 
 grep(s/^asn1pars$/asn1parse/,@ARGV);
@@ -14,7 +16,7 @@ print "#endif\n";
 
 print <<'EOF';
 
-#ifdef SSLEAY_SRC
+#ifdef SSLEAY_SRC  /* Defined only in openssl.c. */
 
 #define FUNC_TYPE_GENERAL	1
 #define FUNC_TYPE_MD		2