Use getsitepackages to find backend dynamic library

traceon/backend/__init__.py

@@ -19,27 +19,36 @@
 ## Attempt 1: load local
 if platform.system() in ['Linux', 'Darwin']:
     local_path = path.join(path.dirname(__file__), 'traceon_backend.so')
+    global_file = 'traceon/backend/traceon_backend.abi3.so'
 else:
     local_path = path.join(path.dirname(__file__), 'traceon_backend.dll')
+    global_file = 'traceon/backend/traceon_backend.pyd'
 
 if path.isfile(local_path):
     backend_lib = C.CDLL(local_path)
 else:
-    ## Attempt 2: load from pip installed path
-    global_path = importlib.util.find_spec('traceon.backend.traceon_backend')
+    ## Attempt 2: use getsitepackages
+    import site
+    paths = site.getsitepackages()
 
+    global_path = None
+
+    for p in paths:
+        if path.isfile(path.join(p, global_file)):
+            global_path = path.join(p, global_file)
+            break
+
     if global_path is None:
         help_txt = '''
         Cannot find Traceon backend (C compiled dynamic library).
         It should have been compiled automatically when installing this package using 'pip3 install traceon'.
         If you're running this package locally (i.e. git clone) you have to build this dynamic library yourself.
         On Linux you can use:
             gcc ./traceon/backend/traceon-backend.c -o ./traceon/backend/traceon-backend.so -lm -shared -fPIC -O3 -ffast-math -std=c99 -march=native'''
-
+        
         raise RuntimeError(help_txt)
-
-    global_path = global_path.origin
-    backend_lib = C.cdll.LoadLibrary(global_path)
+
+    backend_lib = C.CDLL(global_path)
 
 
 TRACING_BLOCK_SIZE = C.c_size_t.in_dll(backend_lib, 'TRACING_BLOCK_SIZE').value