docs/make: generate curl.1 from listed files only

Previously it rendered the page from files matching "*.d" in the correct
directory, which worked fine in git builds when the files were added but
made it easy to forget adding the files to the dist.

Now, only man page sections listed in DPAGES in Makefile.inc will be
used, thus "forcing" us to update this to get the man page right and get
it included in the dist at the same time.

Ref: #5146
Closes #5149

2 files changed, 39 insertions, 40 deletions

diff --git a/docs/cmdline-opts/Makefile.am b/docs/cmdline-opts/Makefile.am
index e6ecf7a6b..0c81b623b 100644
--- a/docs/cmdline-opts/Makefile.am
+++ b/docs/cmdline-opts/Makefile.am
@@ -5,7 +5,7 @@
 #                            | (__| |_| |  _ <| |___
 #                             \___|\___/|_| \_\_____|
 #
-# Copyright (C) 1998 - 2017, Daniel Stenberg, <daniel@haxx.se>, et al.
+# Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
 #
 # This software is licensed as described in the file COPYING, which
 # you should have received as part of this distribution. The terms
@@ -31,4 +31,5 @@ EXTRA_DIST = $(DPAGES) MANPAGE.md gen.pl $(OTHERPAGES) CMakeLists.txt
 all: $(MANPAGE)
 
 $(MANPAGE): $(DPAGES) $(OTHERPAGES) Makefile.inc
-	@PERL@ $(srcdir)/gen.pl mainpage $(srcdir) > $(MANPAGE)
+	@echo "generate $(MANPAGE)"
+	@(cd $(srcdir) && @PERL@ ./gen.pl mainpage $(DPAGES)) > $(MANPAGE)
diff --git a/docs/cmdline-opts/gen.pl b/docs/cmdline-opts/gen.pl
index 63e3504d3..b7a924e8a 100755
--- a/docs/cmdline-opts/gen.pl
+++ b/docs/cmdline-opts/gen.pl
@@ -25,7 +25,7 @@
 
 This script generates the manpage.
 
-Example: gen.pl mainpage > curl.1
+Example: gen.pl <command> [files] > curl.1
 
 Dev notes:
 
@@ -37,12 +37,6 @@ Unfortunately it seems some perls like msysgit can't handle a global input-only
 =end comment
 =cut
 
-my $some_dir=$ARGV[1] || ".";
-
-opendir(my $dh, $some_dir) || die "Can't opendir $some_dir: $!";
-my @s = grep { /\.d$/ && -f "$some_dir/$_" } readdir($dh);
-closedir $dh;
-
 my %optshort;
 my %optlong;
 my %helplong;
@@ -122,7 +116,7 @@ sub added {
 
 sub single {
     my ($f, $standalone)=@_;
-    open(F, "<:crlf", "$some_dir/$f") ||
+    open(F, "<:crlf", "$f") ||
         return 1;
     my $short;
     my $long;
@@ -262,7 +256,7 @@ sub single {
 
 sub getshortlong {
     my ($f)=@_;
-    open(F, "<:crlf", "$some_dir/$f");
+    open(F, "<:crlf", "$f");
     my $short;
     my $long;
     my $help;
@@ -301,14 +295,15 @@ sub getshortlong {
 }
 
 sub indexoptions {
-  foreach my $f (@s) {
-    getshortlong($f);
-  }
+    my (@files) = @_;
+    foreach my $f (@files) {
+        getshortlong($f);
+    }
 }
 
 sub header {
     my ($f)=@_;
-    open(F, "<:crlf", "$some_dir/$f");
+    open(F, "<:crlf", "$f");
     my @d;
     while(<F>) {
         push @d, $_;
@@ -347,12 +342,15 @@ sub listhelp {
 }
 
 sub mainpage {
+    my (@files) = @_;
     # show the page header
     header("page-header");
 
     # output docs for all options
-    foreach my $f (sort @s) {
-        single($f, 0);
+    foreach my $f (sort @files) {
+        if(single($f, 0)) {
+            print STDERR "Can't read $f?\n";
+        }
     }
 
     header("page-footer");
@@ -379,33 +377,33 @@ sub showprotocols {
 }
 
 sub getargs {
-    my $f;
-    do {
-        $f = shift @ARGV;
-        if($f eq "mainpage") {
-            mainpage();
-            return;
-        }
-        elsif($f eq "listhelp") {
-            listhelp();
-            return;
-        }
-        elsif($f eq "single") {
-            showonly(shift @ARGV);
-            return;
-        }
-        elsif($f eq "protos") {
-            showprotocols();
-            return;
-        }
-    } while($f);
+    my ($f, @s) = @_;
+    if($f eq "mainpage") {
+        mainpage(@s);
+        return;
+    }
+    elsif($f eq "listhelp") {
+        listhelp();
+        return;
+    }
+    elsif($f eq "single") {
+        showonly($s[0]);
+        return;
+    }
+    elsif($f eq "protos") {
+        showprotocols();
+        return;
+    }
 
-    print "Usage: gen.pl <mainpage/listhelp/single FILE/protos> [srcdir]\n";
+    print "Usage: gen.pl <mainpage/listhelp/single FILE/protos> [files]\n";
 }
 
 #------------------------------------------------------------------------
 
+my $cmd = shift @ARGV;
+my @files = @ARGV; # the rest are the files
+
 # learn all existing options
-indexoptions();
+indexoptions(@files);
 
-getargs();
+getargs($cmd, @files);