srsran_rf: only build each plugin when found AND enabled

Since [PLUGINNAME]_FOUND are cached variables, some plugins
were always built if they were found once, regardless if
the current value of ENABLE_[PLUGINNAME]

lib/src/phy/rf/CMakeLists.txt

@@ -24,7 +24,7 @@ if(RF_FOUND)
   endif (ENABLE_RF_PLUGINS)
 
   # RF plugins
-  if (UHD_FOUND)
+  if (UHD_FOUND AND ENABLE_UHD)
     add_definitions(-DENABLE_UHD)
     set(SOURCES_UHD rf_uhd_imp.cc)
     if (ENABLE_RF_PLUGINS)
@@ -50,7 +50,7 @@ if(RF_FOUND)
     endif(UHD_ENABLE_CUSTOM_RFNOC)
   endif (UHD_FOUND)
 
-  if (BLADERF_FOUND)
+  if (BLADERF_FOUND AND ENABLE_BLADERF)
     add_definitions(-DENABLE_BLADERF)
     set(SOURCES_BLADE rf_blade_imp.c)
     if (ENABLE_RF_PLUGINS)
@@ -80,7 +80,7 @@ if(RF_FOUND)
     install(TARGETS srsran_rf_soapy DESTINATION ${LIBRARY_DIR})
   endif (SOAPYSDR_FOUND AND ENABLE_SOAPYSDR)
 
-  if(SKIQ_FOUND)
+  if(SKIQ_FOUND AND ENABLE_SKIQ)
     add_executable(skiq_pps_test skiq_pps_test.c)
     target_link_libraries(skiq_pps_test ${SKIQ_LIBRARIES} rt pthread m)
     add_definitions(-DENABLE_SIDEKIQ)
@@ -97,7 +97,7 @@ if(RF_FOUND)
     install(TARGETS srsran_rf_skiq DESTINATION ${LIBRARY_DIR})
   endif(SKIQ_FOUND)
 
-  if (ZEROMQ_FOUND)
+  if (ZEROMQ_FOUND AND ENABLE_ZEROMQ)
     add_definitions(-DENABLE_ZEROMQ)
     set(SOURCES_ZMQ rf_zmq_imp.c rf_zmq_imp_tx.c rf_zmq_imp_rx.c)
     if (ENABLE_RF_PLUGINS)