Add corrected support for Solaris PTYs to run_erl

Two related but slightly separate issues: run_erl doesn't support Solaris's
/dev/ptmx device and run_erl didn't load the necessary STREAMS modules so that
to_erl can provide terminal echo of keyboard input.  This patch adds ifdef'd
support for Solaris and derivatives to open /dev/ptmx directly since adding
the C99 defines to CFLAGS breaks all kinds of other things in the build.  It
also adds ifdef'd ioctl calls to load the necessary STREAMS modules to permit
termios to work.

erts/etc/unix/run_erl.c

@@ -75,6 +75,9 @@
 #ifdef HAVE_SYS_IOCTL_H
 #  include <sys/ioctl.h>
 #endif
+#if defined(__sun) && defined(__SVR4)
+#  include <stropts.h>
+#endif
 
 #include "run_erl.h"
 #include "safe_string.h"    /* sn_printf, strn_cpy, strn_cat, etc */
@@ -864,8 +867,12 @@ static int open_pty_master(char **ptyslave)
 
 /* Use the posix_openpt if working, as this guarantees creation of the 
    slave device properly. */
-#ifdef HAVE_WORKING_POSIX_OPENPT
+#if defined(HAVE_WORKING_POSIX_OPENPT) || (defined(__sun) && defined(__SVR4))
+#  ifdef HAVE_WORKING_POSIX_OPENPT
   if ((mfd = posix_openpt(O_RDWR)) >= 0) {
+#  elif defined(__sun) && defined(__SVR4)
+  if ((mfd = open("/dev/ptmx", O_RDWR)) >= 0) {
+#  endif
       if ((*ptyslave = ptsname(mfd)) != NULL &&
 	  grantpt(mfd) == 0 && 
 	  unlockpt(mfd) == 0) {
@@ -981,6 +988,26 @@ static int open_pty_slave(char *name)
     return -1;
   }
 
+#if defined(__sun) && defined(__SVR4)
+  /* Load the necessary STREAMS modules for Solaris */ 
+  if ((ioctl(sfd, I_FIND, "ldterm")) < 0) {
+    ERROR0(LOG_ERR, "Failed to find ldterm STREAMS module");
+    return -1;
+  }
+  if (ioctl(sfd, I_PUSH, "ptem") < 0) {
+    ERROR0(LOG_ERR, "Failed to push ptem STREAMS module");
+    return -1;
+  }
+  if (ioctl(sfd, I_PUSH, "ldterm") < 0) {
+    ERROR0(LOG_ERR, "Failed to push ldterm STREAMS module");
+    return -1;
+  }
+  if (ioctl(sfd, I_PUSH, "ttcompat") < 0) {
+    ERROR0(LOG_ERR, "Failed to push ttcompat STREAMS module");
+    return -1;
+  }
+#endif
+
 #ifdef DEBUG
   if (tcgetattr(sfd, &tty_rmode) < 0) {
     fprintf(stderr, "Cannot get terminals current mode\n");