Add install script for SDRplay API for use in appveyor build

.appveyor.yml

@@ -97,6 +97,7 @@ for:
       - sh: if [[ ! "${CMAKE_CUSTOM_OPTIONS}" =~ "ENABLE_EXTERNAL_LIBRARIES=ON" ]]; then bash cmake/ci/build_airspyhf.sh; fi
       - sh: if [[ ! "${CMAKE_CUSTOM_OPTIONS}" =~ "ENABLE_EXTERNAL_LIBRARIES=ON" ]]; then bash cmake/ci/build_rtlsdr.sh; fi
       - sh: if [[ ! "${CMAKE_CUSTOM_OPTIONS}" =~ "ENABLE_EXTERNAL_LIBRARIES=ON" ]]; then bash cmake/ci/build_limesuite.sh; fi
+      - sh: if [[ ! "${CMAKE_CUSTOM_OPTIONS}" =~ "ENABLE_EXTERNAL_LIBRARIES=ON" ]]; then bash cmake/ci/build_sdrplay.sh; fi
     before_build:
       - sh: bash -c export
       - sh: bash -c pwd

cmake/ci/build_sdrplay.sh

@@ -0,0 +1,7 @@
+cd $HOME
+mkdir -p external && cd external
+mkdir -p sdrplayapi && cd sdrplayapi
+
+git clone https://github.com/srcejon/sdrplayapi.git
+cd sdrplayapi
+sudo yes | sh install_lib.sh