Added comands building automatically grc applications

Better than manually generated python files but still not perfect as it takes many cmake lines to compile single file and grc files are compiled at every run of make.

Removed also old and not working code for building grc files.
diff --git a/apps/CMakeLists.txt b/apps/CMakeLists.txt
index ce8b205..2dabb0e 100644
--- a/apps/CMakeLists.txt
+++ b/apps/CMakeLists.txt
@@ -19,13 +19,28 @@
 
 include(GrPython)
 
-#GRCC( airprobe_file.grc airprobe_rtlsdr.grc airprobe_usrp.grc ${CMAKE_CURRENT_BINARY_DIR} ) #PK: removed untill I figure out how to do this correctly
+SET(APPS_DIR ${CMAKE_SOURCE_DIR}/apps)
+
+SET(GRCC_COMMAND ${PC_GNURADIO_RUNTIME_PREFIX}/${GR_RUNTIME_DIR}/grcc)
+
+ADD_CUSTOM_TARGET(airprobe_file.py ALL)
+ADD_CUSTOM_COMMAND(
+ TARGET airprobe_file.py
+ COMMAND ${GRCC_COMMAND} -d ${CMAKE_CURRENT_BINARY_DIR} 
+ ARGS "airprobe_file.grc"
+ WORKING_DIRECTORY ${APPS_DIR}
+)
+
+ADD_CUSTOM_TARGET(airprobe_rtlsdr.py ALL)
+ADD_CUSTOM_COMMAND(
+ TARGET airprobe_rtlsdr.py
+ COMMAND ${GRCC_COMMAND} -d ${CMAKE_CURRENT_BINARY_DIR} 
+ ARGS "airprobe_rtlsdr.grc"
+ WORKING_DIRECTORY ${APPS_DIR}
+)
 
 GR_PYTHON_INSTALL(
-    PROGRAMS
-#    ${PYFILES}
     airprobe_file.py
     airprobe_rtlsdr.py
-
     DESTINATION bin
 )