Update signal.h

components/libc/compilers/common/include/sys/signal.h

@@ -215,11 +215,9 @@ int sigaction(int signum, const struct sigaction *act, struct sigaction *oldact)
 #define NSIG    32      /* signal 0 implied */
 #endif /* __ARMCC_VERSION */
 
-#ifndef RT_USING_MUSLLIBC
 /* Some applications take advantage of the fact that <sys/signal.h>
  * and <signal.h> are equivalent in glibc.  Allow for that here.  */
 #include <signal.h>
-#endif /* RT_USING_MUSLLIBC */
 
 #ifndef SIG_ERR
 #define SIG_ERR  ((void (*)(int))-1)