[libc][io] Remove definitions that are not in use

components/libc/posix/io/termios/termios.c

@@ -111,7 +111,6 @@ int tcdrain(int fd)
     return 0;
 }
 
-#if defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
 void cfmakeraw(struct termios *t)
 {
     t->c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP|INLCR|IGNCR|ICRNL|IXON);
@@ -127,4 +126,3 @@ int cfsetspeed(struct termios *tio, speed_t speed)
 {
     return cfsetospeed(tio, speed);
 }
-#endif

components/libc/posix/io/termios/termios.h

@@ -202,10 +202,8 @@ int tcflow (int, int);
 
 pid_t tcgetsid (int);
 
-#if defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
 void cfmakeraw(struct termios *);
 int cfsetspeed(struct termios *, speed_t);
-#endif
 
 #ifdef __cplusplus
 }