dblatex: add missing dependencies

imagemagick, transfig, inkscape, fontconfig and ghostscript was missing.

And pass --use-python-path at install time so that script shebangs end
up with #!/path/to/python instead of #!/path/to/env python.

pkgs/tools/typesetting/tex/dblatex/default.nix

@@ -1,4 +1,5 @@
-{ stdenv, fetchurl, python, libxslt, tetex }:
+{ stdenv, fetchurl, python, libxslt, tetex, imagemagick, transfig, inkscape
+, fontconfig, ghostscript }:
 
 stdenv.mkDerivation rec {
   name = "dblatex-0.3.4";
@@ -8,15 +9,38 @@ stdenv.mkDerivation rec {
     sha256 = "120w3wm07qx0k1grgdhjwm2vpwil71icshjvqznskp1f6ggch290";
   };
 
+  buildInputs = [ python libxslt tetex imagemagick transfig ];
+
+  # TODO: dblatex tries to execute texindy command, but nixpkgs doesn't have
+  # that yet. In Ubuntu, texindy is a part of the xindy package.
+  preConfigure = ''
+    for file in $(find -name "*.py"); do
+        sed -e 's|cmd = \["xsltproc|cmd = \["${libxslt}/bin/xsltproc|g' \
+            -e 's|Popen(\["xsltproc|Popen(\["${libxslt}/bin/xsltproc|g' \
+            -e 's|cmd = "convert|cmd = "${imagemagick}/bin/convert|g' \
+            -e 's|cmd = "fig2dev|cmd = "${transfig}/bin/fig2dev|g' \
+            -e 's|cmd = \["texindy|cmd = ["nixpkgs_is_missing_texindy|g' \
+            -e 's|cmd = \["ps2pdf|cmd = ["${ghostscript}/bin/ps2pdf|g' \
+            -e 's|cmd = "inkscape|cmd = "${inkscape}/bin/inkscape|g' \
+            -e 's|cmd = "epstopdf|cmd = "${tetex}/bin/epstopdf|g' \
+            -e 's|cmd = \["makeindex|cmd = ["${tetex}/bin/makeindex|g' \
+            -e 's|doc.program = "pdflatex"|doc.program = "${tetex}/bin/pdflatex"|g' \
+            -e 's|self.program = "latex"|self.program = "${tetex}/bin/latex"|g' \
+            -e 's|Popen("pdflatex|Popen("${tetex}/bin/pdflatex|g' \
+            -e 's|"fc-match"|"${fontconfig}/bin/fc-match"|g' \
+            -e 's|"fc-list"|"${fontconfig}/bin/fc-list"|g' \
+            -i "$file"
+    done
+
+    sed -i 's|self.install_layout == "deb"|False|' setup.py
+  '';
+
   buildPhase = "true";
 
   installPhase = ''
-    sed -i 's|self.install_layout == "deb"|False|' setup.py
-    python ./setup.py install --prefix=$out
+    python ./setup.py install --prefix="$out" --use-python-path --verbose
   '';
 
-  buildInputs = [ python libxslt tetex ];
-
   meta = {
     description = "A program to convert DocBook to DVI, PostScript or PDF via LaTeX or ConTeXt";
     homepage = http://dblatex.sourceforge.net/;