python3Packages.pdftotext: fix build on darwin

The setup.py file tries to call brew command to locate the Homebrew
version of poppler. Patch the file to stop the call and use the poppler
derivation instead.

pkgs/development/python-modules/pdftotext/default.nix

@@ -1,4 +1,4 @@
-{ lib, buildPythonPackage, fetchPypi, poppler }:
+{ lib, stdenv, buildPythonPackage, fetchPypi, poppler }:
 
 buildPythonPackage rec {
   pname = "pdftotext";
@@ -9,6 +9,11 @@ buildPythonPackage rec {
     sha256 = "a067c121654917ecbe07fbd71c807c34bbdb1ea029e269ddd11925ee7e191d3f";
   };
 
+  postPatch = lib.optionalString stdenv.isDarwin ''
+    substituteInPlace setup.py \
+        --replace '= brew_poppler_include()' '= "${lib.getDev poppler}/include", "${lib.getLib poppler}/lib"'
+  '';
+
   buildInputs = [ poppler ];
 
   meta = with lib; {