platformio.ini: change setting of compiler optimization

- Disable default -Os optimization for size
- Set -O2 explictly in build_flags

This can be tweaked depending on the performance of the resulting builds.

airrohr-firmware/platformio.ini

@@ -25,6 +25,7 @@ build_flags =
   -D PIO_FRAMEWORK_ARDUINO_LWIP2_HIGHER_BANDWIDTH
   -D HTTPCLIENT_1_1_COMPATIBLE=0 -D NO_GLOBAL_SERIAL=0
   -DNDEBUG -DFP_IN_IROM -frandom-seed=b61f78373
+  -O2
 
 build_flags_esp32 =
   -DPIO_FRAMEWORK_ARDUINO_LWIP2_LOW_MEMORY
@@ -88,6 +89,9 @@ extra_scripts = platformio_script.py
 platform_version = espressif8266@2.6.2
 platform_version_esp32 = espressif32@1.11.1 ; using Arduino core 1.0.4
 
+[env]
+build_unflags = -Os
+
 [DISABLEDenv:lolin_d32_pro_debug]
 lang = DE
 platform = ${common.platform_version_esp32}