Load footmisc.sty instead of using outdated code

This is a patch I originally sent to lyx-devel in 2012 with subject
'Load footmisc.sty instead of using copied code from obsolete stblftnt.sty'.
It now takes all comments into account: It works also if the user loads the
package herself, it can be disabled by providing the footmisc feature in a
layout, and it does not use the ugly \AtBeginDocument{}.

lib/chkconfig.ltx

@@ -306,6 +306,7 @@
 \TestPackage{fix-cm}
 \TestPackage{float}
 \TestPackage{fontspec}
+\TestPackage{footmisc}
 \TestPackage{framed}
 \TestPackage{geometry}
 \TestPackage{graphicx}

lib/doc/LaTeXConfig.lyx

@@ -69,6 +69,7 @@
 \html_latex_end </span>
 \author -1379302345 "Julien Rioux" jrioux@lyx.org
 \author -712698321 "Jürgen Spitzmüller" 
+\author -195340706 "Georg Baum"
 \end_header
 
 \begin_body
@@ -7007,6 +7008,46 @@ fixltx2e
 fixltx2e
 \family default
  module.
+\change_inserted -195340706 1415992274
+
+\end_layout
+
+\begin_layout Subsection
+
+\change_inserted -195340706 1415992274
+footmisc
+\end_layout
+
+\begin_layout Description
+
+\change_inserted -195340706 1415992274
+Found: 
+\begin_inset Info
+type  "package"
+arg   "footmisc"
+\end_inset
+
+
+\end_layout
+
+\begin_layout Description
+
+\change_inserted -195340706 1415992274
+CTAN: 
+\family typewriter
+macros/latex/contrib/supported/footmisc/footmisc.sty
+\end_layout
+
+\begin_layout Description
+
+\change_inserted -195340706 1415992274
+Notes: The package 
+\family sans
+footmisc 
+\family default
+is needed to support stable footnotes in chapter titles.
+\change_unchanged
+
 \end_layout
 
 \begin_layout Subsection

src/BufferParams.cpp

@@ -1892,6 +1892,13 @@ bool BufferParams::writeLaTeX(otexstream & os, LaTeXFeatures & features,
 			"User specified LaTeX commands.\n"
 			+ from_utf8(preamble) + '\n';
 
+	// footmisc must be loaded after setspace
+	// Load it here to avoid clashes with footmisc loaded in the user
+	// preamble. For that reason we also pass the options via
+	// \PassOptionsToPackage in getPreamble() and not here.
+	if (features.mustProvide("footmisc"))
+		atlyxpreamble += "\\usepackage{footmisc}\n";
+
 	// subfig loads internally the LaTeX package "caption". As
 	// caption is a very popular package, users will load it in
 	// the preamble. Therefore we must load subfig behind the

src/LaTeXFeatures.cpp

@@ -134,24 +134,6 @@ static docstring const paragraphleftindent_def = from_ascii(
 	"}\n"
 	"{\\end{list}}\n");
 
-static docstring const floatingfootnote_def = from_ascii(
-	"%% Special footnote code from the package 'stblftnt.sty'\n"
-	"%% Author: Robin Fairbairns -- Last revised Dec 13 1996\n"
-	"\\let\\SF@@footnote\\footnote\n"
-	"\\def\\footnote{\\ifx\\protect\\@typeset@protect\n"
-	"    \\expandafter\\SF@@footnote\n"
-	"  \\else\n"
-	"    \\expandafter\\SF@gobble@opt\n"
-	"  \\fi\n"
-	"}\n"
-	"\\expandafter\\def\\csname SF@gobble@opt \\endcsname{\\@ifnextchar[%]\n"
-	"  \\SF@gobble@twobracket\n"
-	"  \\@gobble\n"
-	"}\n"
-	"\\edef\\SF@gobble@opt{\\noexpand\\protect\n"
-	"  \\expandafter\\noexpand\\csname SF@gobble@opt \\endcsname}\n"
-	"\\def\\SF@gobble@twobracket[#1]#2{}\n");
-
 static docstring const binom_def = from_ascii(
 	"%% Binom macro for standard LaTeX users\n"
 	"\\newcommand{\\binom}[2]{{#1 \\choose #2}}\n");
@@ -1050,6 +1032,12 @@ string const LaTeXFeatures::getPackages() const
 	if (mustProvide("subscript") && !isRequired("fixltx2e"))
 		packages << "\\usepackage{subscript}\n";
 
+	// footmisc must be loaded after setspace
+	// Set options here, load the package after the user preamble to
+	// avoid problems with manual loaded footmisc.
+	if (mustProvide("footmisc"))
+		packages << "\\PassOptionsToPackage{stable}{footmisc}\n";
+
 	return packages.str();
 }
 
@@ -1178,8 +1166,6 @@ docstring const LaTeXFeatures::getMacros() const
 	// other
 	if (mustProvide("ParagraphLeftIndent"))
 		macros << paragraphleftindent_def;
-	if (mustProvide("NeedLyXFootnoteCode"))
-		macros << floatingfootnote_def;
 
 	// some problems with tex->html converters
 	if (mustProvide("NeedTabularnewline"))

src/Paragraph.cpp

@@ -1521,7 +1521,7 @@ void Paragraph::Private::validate(LaTeXFeatures & features) const
 			icit->inset->validate(features);
 			if (layout_->needprotect &&
 			    icit->inset->lyxCode() == FOOT_CODE)
-				features.require("NeedLyXFootnoteCode");
+				features.require("footmisc");
 		}
 	}