tests: handle uncommon architecture format for nm

The zlib symbols may not be of type 'T' but rather e.g. 'D' -- instead,
tell nm to emit the POSIX format and also to only emit defined symbols,
not undefined ones. Then we just check if the symbol is listed at all,
regardless of type.

We already depend on -U elsewhere (e.g symbolextractor). There's no real
replacement for it, sadly.

Bug: https://bugs.gentoo.org/938259

test cases/linuxlike/14 static dynamic linkage/verify_static.py

@@ -5,8 +5,12 @@
 
 def handle_common(path):
     """Handle the common case."""
-    output = subprocess.check_output(['nm', path]).decode('utf-8')
-    if 'T zlibVersion' in output:
+    output = subprocess.check_output(['nm', '-UPA', path]).decode('utf-8')
+    # POSIX format. Prints all *defined* symbols, looks like this:
+    # builddir/main_static: zlibVersion T 1190 39
+    # or
+    # builddir/main_static: zlibVersion D 1fde0 30
+    if ': zlibVersion ' in output:
         return 0
     return 1