[Python] Fix setup.py for inplace build (apache#16214)

Previously, `python/setup.py` missed to take the inplace build
case into account when doing file operations (such as finding
paths or copying files), which makes command `make cython` fail.

This PR fixes the issue by checking inplace builds.

python/setup.py

@@ -36,6 +36,7 @@
 CURRENT_DIR = os.path.dirname(__file__)
 FFI_MODE = os.environ.get("TVM_FFI", "auto")
 CONDA_BUILD = os.getenv("CONDA_BUILD") is not None
+INPLACE_BUILD = "--inplace" in sys.argv
 
 
 def get_lib_path():
@@ -46,7 +47,7 @@ def get_lib_path():
     libinfo = {"__file__": libinfo_py}
     exec(compile(open(libinfo_py, "rb").read(), libinfo_py, "exec"), libinfo, libinfo)
     version = libinfo["__version__"]
-    if not CONDA_BUILD:
+    if not CONDA_BUILD and not INPLACE_BUILD:
         lib_path = libinfo["find_lib_path"]()
         libs = [lib_path[0]]
         if "runtime" not in libs[0]:
@@ -214,7 +215,7 @@ def is_pure(self):
 
 
 setup_kwargs = {}
-if not CONDA_BUILD:
+if not CONDA_BUILD and not INPLACE_BUILD:
     with open("MANIFEST.in", "w") as fo:
         for path in LIB_LIST:
             if os.path.isfile(path):
@@ -286,7 +287,7 @@ def long_description_contents():
 )
 
 
-if not CONDA_BUILD:
+if not CONDA_BUILD and not INPLACE_BUILD:
     # Wheel cleanup
     os.remove("MANIFEST.in")
     for path in LIB_LIST: