Merge pull request #25814 from sifmelcara/fix/opencvCMakeLibraryPath

opencv: Fix OpenCV build on non NixOS platform

pkgs/development/libraries/opencv/3.x.nix

@@ -78,6 +78,12 @@ stdenv.mkDerivation rec {
         ln -s "${bootdescFiles}/$name" "$NIX_BUILD_TOP/opencv_contrib/xfeatures2d/src/$name"
       done
     '');
+
+  # This prevents cmake from using libraries in impure paths (which causes build failure on non NixOS)
+  postPatch = ''
+    sed -i '/Add these standard paths to the search paths for FIND_LIBRARY/,/^\s*$/{d}' CMakeLists.txt
+  '';
+
   preConfigure =
     (let version  = "20151201";
          md5      = "808b791a6eac9ed78d32a7666804320e";

pkgs/development/libraries/opencv/default.nix

@@ -35,6 +35,11 @@ stdenv.mkDerivation rec {
       ./no-build-info.patch
     ];
 
+  # This prevents cmake from using libraries in impure paths (which causes build failure on non NixOS)
+  postPatch = ''
+    sed -i '/Add these standard paths to the search paths for FIND_LIBRARY/,/^\s*$/{d}' CMakeLists.txt
+  '';
+
   outputs = [ "out" "dev" ];
 
   buildInputs =