mg: extract child status with WEXITSTATUS

[Scott Cheloha]

Hey,

In the mg(1) *compile* buffer, currently you get incorrect
output like:

        Command exited abnormally with code 256 at [...]

Using the W* macros in <sys/wait.h> corrects this:

        Command exited abnormally with code 1 at [...]

ok?

--
Scott Cheloha

Index: usr.bin/mg/grep.c
===================================================================
RCS file: /cvs/src/usr.bin/mg/grep.c,v
retrieving revision 1.45
diff -u -p -r1.45 grep.c
--- usr.bin/mg/grep.c   12 Oct 2017 14:12:00 -0000      1.45
+++ usr.bin/mg/grep.c   2 Jan 2018 01:42:11 -0000
@@ -4,6 +4,8 @@
 
 #include <sys/queue.h>
 #include <sys/types.h>
+#include <sys/wait.h>
+
 #include <ctype.h>
 #include <libgen.h>
 #include <limits.h>
@@ -180,7 +182,7 @@ compile_mode(const char *name, const cha
        char    *buf;
        size_t   sz;
        ssize_t  len;
-       int      ret, n;
+       int      ret, n, status;
        char     cwd[NFILEN], qcmd[NFILEN];
        char     timestr[NTIME];
        time_t   t;
@@ -223,12 +225,13 @@ compile_mode(const char *name, const cha
        if (ferror(fpipe))
                ewprintf("Problem reading pipe");
        ret = pclose(fpipe);
+       status = WIFEXITED(ret) ? WEXITSTATUS(ret) : 128 + WTERMSIG(ret);
        t = time(NULL);
        strftime(timestr, sizeof(timestr), "%a %b %e %T %Y", localtime(&t));
        addline(bp, "");
-       if (ret != 0)
+       if (status != 0)
                addlinef(bp, "Command exited abnormally with code %d"
-                   " at %s", ret, timestr);
+                   " at %s", status, timestr);
        else
                addlinef(bp, "Command finished at %s", timestr);