View Compilation Error

0_0_25973558_8753.c: In function 'kmp':
0_0_25973558_8753.c:24:5: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
     for(int i=2;str[i-1];i++)
     ^
0_0_25973558_8753.c:24:5: note: use option -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to compile your code