setup.py: make TA_INCLUDE_PATH and TA_LIBRARY_PATH override

This will make it easier to have, for example, both intel and arm
versions co-existing on macOS.

Author: mrjbq7

setup.py

@@ -50,12 +50,10 @@
     library_dirs = [r"c:\ta-lib\c\lib"]
 
 if 'TA_INCLUDE_PATH' in os.environ:
-    paths = os.environ['TA_INCLUDE_PATH'].split(os.pathsep)
-    include_dirs.extend(path for path in paths if path)
+    include_dirs = os.environ['TA_INCLUDE_PATH'].split(os.pathsep)
 
 if 'TA_LIBRARY_PATH' in os.environ:
-    paths = os.environ['TA_LIBRARY_PATH'].split(os.pathsep)
-    library_dirs.extend(path for path in paths if path)
+    library_dirs = os.environ['TA_LIBRARY_PATH'].split(os.pathsep)
 
 if not platform_supported:
     raise NotImplementedError(sys.platform)