style: exit early to reduce indentation

cibuildwheel/macos.py

@@ -275,8 +275,10 @@ def build(options: Options, tmp_path: Path) -> None:
         options.globals.build_selector, options.globals.architectures
     )
 
+    if len(python_configurations) == 0:
+        return
+
     try:
-        if len(python_configurations) > 0:
         before_all_options_identifier = python_configurations[0].identifier
         before_all_options = options.build_options(before_all_options_identifier)
 

cibuildwheel/windows.py

@@ -234,8 +234,10 @@ def build(options: Options, tmp_path: Path) -> None:
         options.globals.build_selector, options.globals.architectures
     )
 
+    if len(python_configurations) == 0:
+        return
+
     try:
-        if len(python_configurations) > 0:
         before_all_options_identifier = python_configurations[0].identifier
         before_all_options = options.build_options(before_all_options_identifier)