Re-enable building of docs

Debian patch fix-pdf-generation:
Description: Fix PDF refman generation
 This just remove a pre-latex-processing hack that just breaks nowadays.
 The Makefile.in was updated by hand, since autostuff is way old and
 apparently more work is needed to make regeneration work properly.
Author: Yann Dirson <dirson@debian.org>
Bug-Debian: http://bugs.debian.org/718100

Debian patch enable-docs.patch:
Author: Manuel A. Fernandez Montecelo <manuel.montezelo@gmail.com>

Makefile.am

@@ -1,7 +1,7 @@
 
 ACLOCAL_AMFLAGS = -I m4
 
-SUBDIRS = src demo # test (does not build) # docs (overflows pdflatex)
+SUBDIRS = src demo docs # test (does not build)
 DIST_SUBDIRS = $(SUBDIRS) msvc
 
 pkgconfigdir = $(libdir)/pkgconfig

docs/Makefile.am

@@ -36,9 +36,7 @@ stamp-doxygen: doxygen.cfg stamp-eps
 
 latex/ftgl.pdf: stamp-latex
 stamp-latex: stamp-doxygen
-	rm -f latex/ftgl.tex latex/ftgl.pdf
-	mv latex/refman.tex latex/ftgl.tex
-	$(SED) -e 's/setlength{/renewcommand{/' < latex/ftgl.tex > latex/refman.tex
+	rm -f latex/ftgl.pdf
 	cd latex && $(MAKE) $(AM_CFLAGS) refman.pdf || (cat refman.log; exit 1)
 	mv latex/refman.pdf latex/ftgl.pdf
 	touch stamp-latex