lp_solve: fixed build error due to defining isnan

pkgs/applications/science/math/lp_solve/default.nix

@@ -10,10 +10,16 @@ stdenv.mkDerivation rec {
     sha256 = "176c7f023mb6b8bfmv4rfqnrlw88lsg422ca74zjh19i2h5s69sq";
   };
 
+  patches = [ ./isnan.patch ];
+
   buildCommand = ''
     . $stdenv/setup
     tar xvfz $src
     (
+    cd lp_solve*
+    eval patchPhase
+    )
+    (
     cd lp_solve*/lpsolve55
     bash ccc
     mkdir -pv $out/lib
@@ -37,7 +43,6 @@ stdenv.mkDerivation rec {
     license     = licenses.gpl2Plus;
     maintainers = with maintainers; [ smironov ];
     platforms   = platforms.unix;
-    broken      = true;
   };
 
 }