Fix

platformio.ini

@@ -9,7 +9,7 @@ src_dir     = Src
 ;
 ; Choose one or all variants get built
 ;
-default_envs = VARIANT_ADC         ; Variant for control via ADC input
+;default_envs = VARIANT_ADC         ; Variant for control via ADC input
 ;default_envs = VARIANT_USART       ; Variant for Serial control via USART3 input
 ;default_envs = VARIANT_NUNCHUK     ; Variant for Nunchuk controlled vehicle build
 ;default_envs = VARIANT_PPM         ; Variant for RC-Remotes with PPM-Sum signal
@@ -40,7 +40,6 @@ build_flags =
     -T./STM32F103RCTx_FLASH.ld
     -lc
     -lm
-#    -flto
     -g -ggdb        ; to generate correctly the 'firmware.elf' for STM STUDIO vizualization
     -D VARIANT_ADC
 
@@ -62,7 +61,7 @@ build_flags =
     -DSTM32F103xE
     -T./STM32F103RCTx_FLASH.ld
     -lc
-    -l
+    -lm
     -g -ggdb        ; to generate correctly the 'firmware.elf' for STM STUDIO vizualization
     -D VARIANT_USART