Port vision to AIX (#8914)

Co-authored-by: Nicolas Hug <[email protected]>

Author: KamathForAIX

setup.py

@@ -194,7 +194,7 @@ def make_C_extension():
 
 def find_libpng():
     # Returns (found, include dir, library dir, library name)
-    if sys.platform in ("linux", "darwin"):
+    if sys.platform in ("linux", "darwin", "aix"):
         libpng_config = shutil.which("libpng-config")
         if libpng_config is None:
             warnings.warn("libpng-config not found")

torchvision/datasets/mnist.py

@@ -514,7 +514,7 @@ def read_sn3_pascalvincent_tensor(path: str, strict: bool = True) -> torch.Tenso
         data = f.read()
 
     # parse
-    if sys.byteorder == "little":
+    if sys.byteorder == "little" or sys.platform == "aix":
         magic = get_int(data[0:4])
         nd = magic % 256
         ty = magic // 256
@@ -527,7 +527,7 @@ def read_sn3_pascalvincent_tensor(path: str, strict: bool = True) -> torch.Tenso
     torch_type = SN3_PASCALVINCENT_TYPEMAP[ty]
     s = [get_int(data[4 * (i + 1) : 4 * (i + 2)]) for i in range(nd)]
 
-    if sys.byteorder == "big":
+    if sys.byteorder == "big" and not sys.platform == "aix":
         for i in range(len(s)):
             s[i] = int.from_bytes(s[i].to_bytes(4, byteorder="little"), byteorder="big", signed=False)