Downgrade qt version from 4.12.1 to 4.9 (current LTS) (Doc says 4.6 required)

conda/opencv/meta.yaml

@@ -80,7 +80,7 @@ requirements:
     - harfbuzz                       # [unix]
     - libpng
     - ffmpeg                         # [not win]
-    - qt 5.12.1                      # [not osx and not aarch64 and not ppc64le]
+    - qt 5.9                         # [not osx and not aarch64 and not ppc64le]
     # - liblapacke
     - freetype
     - glib                           # [unix]
@@ -89,7 +89,7 @@ requirements:
     - harfbuzz                       # [unix]
     # Don't depend on python in the run section
     # py-opencv will depend on python
-    - qt 5.12                        # [not osx and not aarch64 and not ppc64le]
+    - qt 5.9                         # [not osx and not aarch64 and not ppc64le]
     # https://github.com/conda-forge/opencv-feedstock/issues/174
     # Seems like the OSX ABI has changed between 2.9 and 2.10???
     # That or a dependency wasn't merged in
@@ -107,7 +107,7 @@ test:
       - liblapack * *mkl              # [py==37 and linux64]
       - cmake
       - ninja
-      - qt 5.12.1                     # [linux64]
+      - qt 5.9                     # [linux64]
     files:
       - CMakeLists.txt
       - test.cpp