configure: Don't emit _PRESENT macros

Do not put macros like MBED_CONF_FILESYSTEM_PRESENT or
MBED_CONF_EVENTS_PRESENT into the applicaiton's generated
mbed_config.cmake file. We will depend on Mbed OS CMake files for each
of these components to define the _PRESENT macro in a
target_compile_definitions() block for the e.g. filesystem or events
CMake targets.

news/20200929160957.misc

@@ -0,0 +1 @@
+Don't emit _PRESENT macros. Depend on Mbed OS to define these from CMake.

src/mbed_tools/build/_internal/cmake_file.py

@@ -47,7 +47,7 @@ def _render_mbed_config_cmake_template(
     """
     env = jinja2.Environment(loader=jinja2.PackageLoader("mbed_tools.build", str(TEMPLATES_DIRECTORY)),)
     template = env.get_template(TEMPLATE_NAME)
-    options = list(config.options.values())
+    options = [x for x in config.options.values() if not x.key.endswith(".present")]
     macros = list(config.macros.values())
     supported_c_libs = [x for x in target_build_attributes["supported_c_libs"][toolchain_name.lower()]]