Append prefix to plugin name when running on Android.

Android libraries can't be placed inside subdirectory, so to
distinguish plugins from regular libraries the new prefix is used.

plugins/samplesource/bladerf1input/CMakeLists.txt

@@ -33,12 +33,12 @@ if(NOT SERVER_MODE)
         bladerf1inputgui.h
     )
 
-    set(TARGET_NAME inputbladerf1)
+    set(TARGET_NAME ${PLUGINS_PREFIX}inputbladerf1)
     set(TARGET_LIB "Qt::Widgets")
     set(TARGET_LIB_GUI "sdrgui")
     set(INSTALL_FOLDER ${INSTALL_PLUGINS_DIR})
 else()
-    set(TARGET_NAME inputbladerf1srv)
+    set(TARGET_NAME ${PLUGINSSRV_PREFIX}inputbladerf1srv)
     set(TARGET_LIB "")
     set(TARGET_LIB_GUI "")
     set(INSTALL_FOLDER ${INSTALL_PLUGINSSRV_DIR})