cmake: Add warn about cross compiling, disable android

externals/nx_tzdb/CMakeLists.txt

@@ -20,8 +20,10 @@ endif()
 if ("${GNU_DATE}" STREQUAL "GNU_DATE-NOTFOUND")
     set(CAN_BUILD_NX_TZDB false)
 endif()
-if ("${CMAKE_SYSTEM_NAME}" STREQUAL "Windows")
+if ("${CMAKE_SYSTEM_NAME}" STREQUAL "Windows" OR ANDROID)
     # tzdb_to_nx currently requires a posix-compliant host
+    # MinGW and Android are handled here due to the executable format being different from the host system
+    # TODO (lat9nq): cross-compiling support
     set(CAN_BUILD_NX_TZDB false)
 endif()