cpp: do not pass #error into output stream, warn about it and exit non-0

*** 1024,1035 ****
                          while (*inp != '\n')    /* pass text */
                                  p = cotoken(p);
          } else if (np == pragmaloc) {           /* pragma */
                  while (*inp != '\n')            /* pass text */
                          p = cotoken(p);
-         } else if (np == errorloc) {            /* error */
  #ifdef  EXIT_ON_ERROR
                  if (trulvl > 0) {
                          char ebuf[BUFFERSIZ];
  
                          p = ebuf;
                          while (*inp != '\n') {
--- 1024,1035 ----
                          while (*inp != '\n')    /* pass text */
                                  p = cotoken(p);
          } else if (np == pragmaloc) {           /* pragma */
                  while (*inp != '\n')            /* pass text */
                          p = cotoken(p);
  #ifdef EXIT_ON_ERROR
+         } else if (np == errorloc) {            /* error */
                  if (trulvl > 0) {
                          char ebuf[BUFFERSIZ];
  
                          p = ebuf;
                          while (*inp != '\n') {
*** 1044,1056 ****
                          }
                          *p = '\0';
                          pperror(ebuf);
                          exit(exfail);
                  }
- #else
-                 while (*inp != '\n')            /* pass text */
-                         p = cotoken(p);
  #endif
          } else if (np==lneloc) {/* line */
                  if (flslvl==0 && pflag==0) {
                          outp=inp=p;
                          *--outp='#';
--- 1044,1053 ----