For some reason there is no -mmcu=atmega32u4 option here.
Generating function prototypes...
"C:\\Users\\justi\\AppData\\Local\\Arduino15\\packages\\arduino\\tools\\avr-gcc\\7.3.0-atmel3.6.1-arduino7/bin/avr-g++"
-c -g -Os -w -std=gnu++11
-fpermissive -fno-exceptions -ffunction-sections
-fdata-sections -fno-threadsafe-statics
-Wno-error=narrowing -flto -w -x c++ -E -CC
-DF_CPU=16000000L -DARDUINO=10816
-DARDUINO_AVR_MICRO -DARDUINO_ARCH_AVR
-DUSB_VID=0x2341 -DUSB_PID=0x8037
"-DUSB_MANUFACTURER=\"Unknown\"" "-DUSB_PRODUCT=\"Arduino Micro\""
"-IC:\\Users\\justi\\AppData\\Local\\Arduino15\\packages\\arduino\\hardware\\avr\\1.8.3\\cores\\arduino"
"-IC:\\Users\\justi\\AppData\\Local\\Arduino15\\packages\\arduino\\hardware\\avr\\1.8.3\\variants\\micro"
"C:\\Users\\justi\\AppData\\Local\\Temp\\arduino_build_106000\\sketch\\sketch_sep19a.ino.cpp"
-o "C:\\Users\\justi\\AppData\\Local\\Temp\\arduino_build_106000\\preproc\\ctags_target_for_gcc_minus_e.cpp"