Let mingw_execve() return an int

This is in the great tradition of POSIX. Original fix by Olivier Refalo.

Signed-off-by: Johannes Schindelin <[email protected]>

Author: dscho

compat/mingw.c

@@ -1131,19 +1131,20 @@ static int try_shell_exec(const char *cmd, char *const *argv, char **env)
 	return pid;
 }
 
-static void mingw_execve(const char *cmd, char *const *argv, char *const *env)
+static int mingw_execve(const char *cmd, char *const *argv, char *const *env)
 {
 	/* check if git_command is a shell script */
 	if (!try_shell_exec(cmd, argv, (char **)env)) {
 		int pid, status;
 
 		pid = mingw_spawnve(cmd, (const char **)argv, (char **)env, 0);
 		if (pid < 0)
-			return;
+			return -1;
 		if (waitpid(pid, &status, 0) < 0)
 			status = 255;
 		exit(status);
 	}
+	return -1;
 }
 
 int mingw_execvp(const char *cmd, char *const *argv)