Fix check deciding on assertions and checks

Instead of relying on “buildtype”, consider “optimization” and “debug”.

Thanks @nirbheek!

meson.build

@@ -6,8 +6,7 @@ host_os = host_os_family
 cc = meson.get_compiler('c')
 
 frida_component_cflags = []
-buildtype = get_option('buildtype')
-if buildtype == 'release' or buildtype == 'minsize'
+if get_option('optimization') in ['2', '3', 's'] and not get_option('debug')
   frida_component_cflags += [
     '-DG_DISABLE_ASSERT',
     '-DG_DISABLE_CHECKS',