Fix false positives ignoredReturnValue about some posix interfaces. Remove redundant strsignal() output from signal handler

cfg/posix.cfg

@@ -1695,7 +1695,6 @@
   </function>
   <!-- char *asctime_r(const struct tm *tm, char *buf); -->
   <function name="asctime_r">
-    <use-retval/>
     <noreturn>false</noreturn>
     <leak-ignore/>
     <arg nr="1">
@@ -1708,7 +1707,6 @@
   </function>
   <!-- char *ctime_r(const time_t *timep, char *buf); -->
   <function name="ctime_r">
-    <use-retval/>
     <noreturn>false</noreturn>
     <leak-ignore/>
     <arg nr="1">
@@ -1721,7 +1719,6 @@
   </function>
   <!-- struct tm *gmtime_r(const time_t *timep, struct tm *result); -->
   <function name="gmtime_r">
-    <use-retval/>
     <noreturn>false</noreturn>
     <leak-ignore/>
     <arg nr="1">

cli/cppcheckexecutor.cpp

@@ -346,14 +346,11 @@ static void CppcheckSignalHandler(int signo, siginfo_t * info, void * context)
     }
 #endif
     const char * const signame = signal_name(signo);
-    const char * const sigtext = strsignal(signo);
     bool bPrintCallstack=true;
     const bool isaddressonstack = isAddressOnStack(info->si_addr);
     FILE* f = (CppCheckExecutor::getExceptionOutput()=="stderr") ? stderr : stdout;
     fputs("Internal error: cppcheck received signal ", f);
     fputs(signame, f);
-    fputs(", ", f);
-    fputs(sigtext, f);
     switch (signo) {
     case SIGBUS:
         switch (info->si_code) {

test/cfg/posix.c

@@ -182,4 +182,8 @@ void timet_h() {
   struct timespec* ptp;
   // cppcheck-suppress uninitvar
   clock_settime(CLOCK_REALTIME, ptp);
+  
+  time_t clock = time(0);
+  char buf[26];
+  ctime_r(&clock, buf);
 }