Compilation error due to C99 mode

[vitasam]

Hi,
default compilation failed due to missed C99 mode:

src/main.c: In function 'redraw_lcd':
src/main.c:375:3: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
   for(int a=0; a < STACK_SIZE; a++) {
   ^
src/main.c:375:3: note: use option -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to compile your code
src/main.c: In function 'add_edit_key':
...

[vitasam]

works Ok with latest Version 7-2018 GNU Arm toolchain