Make generated files read-only

This is an attempt to discouraged manual changes of generated files,
as people have done so, just to get their changes over-written next
time those files are re-generated.

Reference: https://github.com/openssl/openssl/discussions/28269

Reviewed-by: Dmitry Belyavskiy <beldmit@gmail.com>
Reviewed-by: Paul Dale <ppzgs1@gmail.com>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/28612)

Configurations/descrip.mms.tmpl

@@ -950,7 +950,9 @@ EOF
       } elsif (-f $inprologue) {
           my $local_scripture .= <<"EOF";
 $outprologue : $inprologue
+	IF F$SEARCH("$outprologue") .EQS. "" SET FILE/PROT=(O:RWD) $outprologue
 	COPY $inprologue $outprologue
+	SET FILE/PROT=(O:RD) $outprologue
 EOF
           $includefile_cache{$outprologue} = $local_scripture;
 
@@ -962,7 +964,9 @@ EOF
       } elsif (-f $inepilogue) {
           my $local_scripture .= <<"EOF";
 $outepilogue : $inepilogue
+	IF F$SEARCH("$outepilogue") .EQS. "" SET FILE/PROT=(O:RWD) $outepilogue
 	COPY $inepilogue $outepilogue
+	SET FILE/PROT=(O:RD) $outepilogue
 EOF
           $includefile_cache{$outepilogue} = $local_scripture;
 
@@ -1116,7 +1120,9 @@ EOF
 
           return <<"EOF";
 $args{src} : $gen0 $deps
+	IF F$SEARCH("\$\@") .EQS. "" SET FILE/PROT=(O:RWD) \$\@
 	\$(PERL)$perlmodules $dofile "-o$target{build_file}" $gen0$gen_args > \$\@
+	SET FILE/PROT=(O:RD) \$\@
 $decc_include_scripture
 EOF
       } elsif (grep { $_ eq $gen0 } @{$unified_info{programs}}) {
@@ -1479,10 +1485,11 @@ EOF
                            rel2abs($config{builddir}));
       return <<"EOF";
 $script : $sources configdata.pm
-        \$(PERL) "-I\$(BLDDIR)" "-Mconfigdata" $dofile -
+	IF F$SEARCH("$script") .EQS. "" SET FILE/PROT=(S:RWED,O:RWED,G:RE,W:RE) $script
+	\$(PERL) "-I\$(BLDDIR)" "-Mconfigdata" $dofile -
 	    "-o$target{build_file}" $sources > $script
-        SET FILE/PROT=(S:RWED,O:RWED,G:RE,W:RE) $script
+	SET FILE/PROT=(S:RWED,O:RE,G:RE,W:RE) $script
-        PURGE $script
+	PURGE $script
 EOF
   }
   ""    # Important!  This becomes part of the template result.

Configurations/unix-Makefile.tmpl

@@ -1683,7 +1683,9 @@ EOF
 
           return <<"EOF";
 $args{src}: $gen0 $deps
+	if [ -r "\$@" ]; then chmod u+w \$@; fi
 	\$(PERL)$perlmodules "$dofile" "-o$target{build_file}" $gen0$gen_args > \$@
+	chmod a-w \$@
 EOF
       } elsif (grep { $_ eq $gen0 } @{$unified_info{programs}}) {
           #
@@ -2040,10 +2042,11 @@ EOF
                            rel2abs($config{builddir}));
       return <<"EOF";
 $script: $sources configdata.pm
+	if [ -r "$script" ]; then chmod u+w $script; fi
 	\$(RM) "$script"
 	\$(PERL) "-I\$(BLDDIR)" -Mconfigdata "$dofile" \\
 	    "-o$target{build_file}" $sources > "$script"
-	chmod a+x $script
+	chmod a+x,a-w $script
 EOF
   }
   sub generatedir {

Configurations/windows-makefile.tmpl

@@ -845,7 +845,9 @@ EOF
 
           return <<"EOF";
 $args{src}: "$gen0" $deps
+	if exist \$@ attrib -r \$@
 	"\$(PERL)"$perlmodules "$dofile" "-o$target{build_file}" "$gen0"$gen_args > \$@
+	attrib +r \$@
 EOF
       } elsif (grep { $_ eq $gen0 } @{$unified_info{programs}}) {
           #
@@ -1054,8 +1056,10 @@ EOF
                            rel2abs($config{builddir}));
       return <<"EOF";
 $script: $sources configdata.pm
+	if exist $script attrib -r $script
 	"\$(PERL)" "-I\$(BLDDIR)" -Mconfigdata "$dofile" \\
 	    "-o$target{build_file}" $sources > \$@
+	attrib +r $script
 EOF
   }
   sub generatedir {