Backport: Add workaround for problem visible in C++ code

In C code, p SysBase gives $1 = (struct ExecBase *)addr, however when
first C++ debugging information is loaded, this is change into
$1 = (ExecBase *)addr. This results in $SysBase = (ExecBase *)addr and
gdb complaining about ExecBase type not being known.

The hack makes sure that output is always $SysBase = (struct ExecBase*)addr

Author: deadwood

developer/debug/gdb/_gdbinit

@@ -23,7 +23,13 @@ define symbol_check
   ignore-errors p $arg0
   end_log
 
+  # Turns $1 = (type)addr into $symbol = (type)addr
   shell sed -i -e '/^[^\$]/d' -e 's/^\$[0-9]* =/set $'$arg0' =/' symbol.tmp
+
+  # Hack. In case of C++, type is displayed without struct keyword and loading fails.
+  # Add struct keyword uncoditionally to any type after first removing it if it was there
+  shell sed -i -e 's/(APTR)//' -e 's/= (struct /= (/' -e 's/= (/= (struct /' symbol.tmp
+
   source symbol.tmp
 end