options: accept compiler and built-in options in --reconfigure and "meson configure"

Follow the same logic that is used at the end of the first invocation.
This fixes

   meson setup --reconfigure -Db_ndebug=true

on a project that has no language that defines b_ndebug.

Signed-off-by: Paolo Bonzini <[email protected]>
(cherry picked from commit 8dcc9d3)

Author: bonzini

mesonbuild/options.py

@@ -1057,8 +1057,13 @@ def replace(v: str) -> str:
     def set_option_maybe_root(self, o: OptionKey, new_value: str) -> bool:
         if o in self.options:
             return self.set_option(o, new_value)
-        o = o.as_root()
-        return self.set_option(o, new_value)
+        if self.accept_as_pending_option(o):
+            old_value = self.pending_options.get(o, None)
+            self.pending_options[o] = new_value
+            return old_value is None or str(old_value) == new_value
+        else:
+            o = o.as_root()
+            return self.set_option(o, new_value)
 
     def set_from_configure_command(self, D_args: T.List[str], U_args: T.List[str]) -> bool:
         dirty = False

unittests/optiontests.py

@@ -208,6 +208,10 @@ def test_b_nonexistent(self):
         assert optstore.accept_as_pending_option(OptionKey('b_ndebug'))
         assert not optstore.accept_as_pending_option(OptionKey('b_whatever'))
 
+    def test_reconfigure_b_nonexistent(self):
+        optstore = OptionStore(False)
+        optstore.set_from_configure_command(['b_ndebug=true'], [])
+
     def test_subproject_nonexistent(self):
         optstore = OptionStore(False)
         subprojects = {'found'}