mkoctfile exits with 0 if gcc failed

[Andreas Weber]

Dear maintainers,

mkoctfile returns 0 if the called subprocess returns != 0.

One example:
~/src/octave-src$ LC_ALL=C mkoctfile nonexistentfile.cpp
g++: error: nonexistentfile.cpp: No such file or directory
g++: fatal error: no input files
compilation terminated.
g++: error: nonexistentfile.o: No such file or directory
~/src/octave-src$ echo $?
0

This is because system returns the exit status of the called process in
the upper 8bits. According to "man wait" WIFEXITED and WEXITSTSTUS
should be used for the bit shifting and masking stuff.

I propose the following patch:

diff -r 0ede4dbb37f1 src/mkoctfile.in.cc
--- a/src/mkoctfile.in.cc       Sun Mar 30 14:18:43 2014 -0700
+++ b/src/mkoctfile.in.cc       Wed Jun 04 14:42:58 2014 +0200
@@ -344,7 +344,10 @@
 {
   if (debug)
     std::cout << cmd << std::endl;
-  return system (cmd.c_str ());
+  int result = system (cmd.c_str ());
+  if (WIFEXITED (result))
+    result = WEXITSTATUS (result);
+  return result;
 }


which works but I get the following warnings when compiling mkoctfile on
debian wheezy 64bit with gcc 4.7.2:
mkoctfile.cc: In function ‘int run_command(const string&)’:
mkoctfile.cc:348:7: warning: use of old-style cast [-Wold-style-cast]
mkoctfile.cc:349:14: warning: use of old-style cast [-Wold-style-cast]


The old style cast is defined in /usr/include/stdlib.h:55
#ifdef __USE_BSD
.....
#define __WAIT_INT(status)      (*(int *) &(status))

Any hints what should be done to avoid these warnings?

-- Andy