CI: Enable serial backend on OSX

Compile Libiio against libserialport to activate the serial backend on
OSX.

Signed-off-by: Paul Cercueil <[email protected]>

Author: pcercuei

azure-pipelines.yml

@@ -328,15 +328,15 @@ stages:
     - script: |
         set -e
         mkdir build && cd build
-        cmake .. -Werror=dev -DCOMPILE_WARNING_AS_ERROR=ON -DOSX_PACKAGE=ON -DCPP_BINDINGS=ON -DPYTHON_BINDINGS=ON -DWITH_EXAMPLES=ON -DWITH_SERIAL_BACKEND=OFF -DWITH_ZSTD=OFF
+        cmake .. -Werror=dev -DCOMPILE_WARNING_AS_ERROR=ON -DOSX_PACKAGE=ON -DCPP_BINDINGS=ON -DPYTHON_BINDINGS=ON -DWITH_EXAMPLES=ON -DWITH_SERIAL_BACKEND=ON -DWITH_ZSTD=OFF
         make
         sudo make install
         cd ..
       displayName: 'Build'
     - script: |
         set -e
         mkdir build_tar && cd build_tar
-        cmake .. -Werror=dev -DCOMPILE_WARNING_AS_ERROR=ON -DOSX_PACKAGE=OFF -DENABLE_PACKAGING=ON -DCPP_BINDINGS=ON -DPYTHON_BINDINGS=ON -DWITH_SERIAL_BACKEND=OFF -DWITH_ZSTD=OFF -DCPACK_SYSTEM_NAME=${ARTIFACTNAME}
+        cmake .. -Werror=dev -DCOMPILE_WARNING_AS_ERROR=ON -DOSX_PACKAGE=OFF -DENABLE_PACKAGING=ON -DCPP_BINDINGS=ON -DPYTHON_BINDINGS=ON -DWITH_SERIAL_BACKEND=ON -DWITH_ZSTD=OFF -DCPACK_SYSTEM_NAME=${ARTIFACTNAME}
         make
         make package
         mv ../CI/azure/macos_tar_fixup.sh .
@@ -347,7 +347,7 @@ stages:
     - script: |
         set -e
         cd build
-        cmake .. -Werror=dev -DCOMPILE_WARNING_AS_ERROR=ON -DCPP_BINDINGS=ON -DPYTHON_BINDINGS=ON -DWITH_DOC=ON
+        cmake .. -Werror=dev -DCOMPILE_WARNING_AS_ERROR=ON -DCPP_BINDINGS=ON -DPYTHON_BINDINGS=ON -DWITH_DOC=ON -DWITH_SERIAL_BACKEND=ON
         make
         cd ..
       displayName: 'Build With Doc'