Install fftw before conda build for azure pipeline also for mac

Author: mikaem

azure-pipelines.yml

@@ -24,7 +24,7 @@ jobs:
   - bash: |
       conda config --add channels conda-forge
       conda config --set always_yes yes
-      conda install -n root conda-build
+      conda install -n root conda-build numpy fftw
     displayName: Set up Anaconda
 
   - bash: |