wmlunits: Fix issue where the process name becomes "w" instead of "wmlunits"

The basic string type in Python 3 is equivalent to a wchar_t array,
which means that the second byte of every ASCII string is always zero,
causing the string to appear truncated after the first character when
calling C library functions that expect a single or multibyte encoding
(e.g. UTF-8). Just using a byte array does the trick to get a proper
single-byte ASCII string.

data/tools/wmlunits

@@ -559,7 +559,7 @@ if __name__ == '__main__':
     try:
         import ctypes
         libc = ctypes.CDLL("libc.so.6")
-        libc.prctl(15, "wmlunits", 0, 0, 0)
+        libc.prctl(15, b"wmlunits", 0, 0, 0)
     except: # oh well...
         pass