gdb/solib: make solib_ops::solib_create_inferior_hook optional

The solib-target implementation of solib_create_inferior_hook is empty.
Make that method / function pointer optional.

Change-Id: Ie27b8d2c4fc6df74069ac8f88fbe69cf88a6662d
Reviewed-By: Guinevere Larsen <[email protected]>

Author: simark

gdb/solib-target.c

@@ -256,12 +256,6 @@ solib_target_current_sos (void)
   return sos;
 }
 
-static void
-solib_target_solib_create_inferior_hook (int from_tty)
-{
-  /* Nothing needed.  */
-}
-
 static void
 solib_target_relocate_section_addresses (solib &so, target_section *sec)
 {
@@ -396,7 +390,7 @@ const solib_ops solib_target_so_ops =
   solib_target_relocate_section_addresses,
   nullptr,
   nullptr,
-  solib_target_solib_create_inferior_hook,
+  nullptr,
   solib_target_current_sos,
   nullptr,
   solib_target_in_dynsym_resolve_code,

gdb/solib.c

@@ -1317,7 +1317,8 @@ solib_create_inferior_hook (int from_tty)
 {
   const solib_ops *ops = gdbarch_so_ops (current_inferior ()->arch ());
 
-  ops->solib_create_inferior_hook (from_tty);
+  if (ops->solib_create_inferior_hook != nullptr)
+    ops->solib_create_inferior_hook (from_tty);
 }
 
 /* See solib.h.  */