Check for PyZMQ at runtime instead of compile time to support

cross-compiling.

CMakeLists.txt

@@ -82,10 +82,10 @@ endif()
 # Find PyZMQ bindings
 ########################################################################
 include(GrPython)
-GR_PYTHON_CHECK_MODULE("PyZMQ" "zmq" "int(zmq.__version__.split('.')[0]) >= 13" PYZMQ_FOUND)
+#GR_PYTHON_CHECK_MODULE("PyZMQ" "zmq" "int(zmq.__version__.split('.')[0]) >= 13" PYZMQ_FOUND)
-if(NOT PYZMQ_FOUND)
+#if(NOT PYZMQ_FOUND)
-    message(FATAL_ERROR "Python ZMQ bindings not found.")
+#    message(FATAL_ERROR "Python ZMQ bindings not found.")
-endif()
+#endif()
 
 ########################################################################
 # Setup the include and linker paths

python/__init__.py

@@ -51,6 +51,12 @@ from air_modes_swig import *
 
 # import any pure python here
 #
+
+try:
+    import zmq
+except ImportError:
+    raise RuntimeError("PyZMQ not found! Please install libzmq and PyZMQ to run gr-air-modes")
+
 from rx_path import rx_path
 from zmq_socket import zmq_pubsub_iface
 from parse import *