Allow libc to use different fstat variants

Running on my dev machine, ArchLinux, get fstat while Ubuntu CI machine
finds newfstatat

Author: cmaloney

Lib/test/test_fileio.py

@@ -383,8 +383,14 @@ def test_syscalls_read(self):
             """,
             _strace_flags
         )
-        self.assertEqual(calls, ['openat', 'fstat', 'ioctl', 'lseek',
-                                 'lseek', 'fstat', 'read', 'read', 'close'])
+
+        # There are a number of related syscalls used to implement `fstat` in
+        # a libc (ex. fstat, newfstatat). Default to fstat, but if we see the
+        # system using a variant, allow that
+        fstat = next((sc for sc in calls if 'fstat' in sc), 'fstat')
+
+        self.assertEqual(calls, ['openat', fstat, 'ioctl', 'lseek',
+                                 'lseek', fstat, 'read', 'read', 'close'])
 
         # Focus on just `read()`
         calls = strace_helper.get_syscalls(
@@ -393,7 +399,7 @@ def test_syscalls_read(self):
             cleanup="f.close()",
             strace_flags=_strace_flags
         )
-        self.assertEqual(calls, ['lseek', 'fstat', 'read', 'read'])
+        self.assertEqual(calls, ['lseek', fstat, 'read', 'read'])
 
         # Readall in binary mode
         calls = strace_helper.get_syscalls(
@@ -404,8 +410,8 @@ def test_syscalls_read(self):
             """,
             _strace_flags
         )
-        self.assertEqual(calls, ['openat', 'fstat', 'ioctl', 'lseek', 'lseek',
-                                 'fstat', 'read', 'read', 'close'])
+        self.assertEqual(calls, ['openat', fstat, 'ioctl', 'lseek', 'lseek',
+                                 fstat, 'read', 'read', 'close'])
 
         # Readall in text mode
         calls = strace_helper.get_syscalls(
@@ -416,8 +422,8 @@ def test_syscalls_read(self):
             """,
             _strace_flags
         )
-        self.assertEqual(calls, ['openat', 'fstat', 'ioctl', 'lseek', 'lseek',
-                                 'fstat', 'read', 'read', 'close'])
+        self.assertEqual(calls, ['openat', fstat, 'ioctl', 'lseek', 'lseek',
+                                 fstat, 'read', 'read', 'close'])
 
 
 class CAutoFileTests(AutoFileTests, unittest.TestCase):