Fix managing weak symbols.

Weak symbols where not being managed correctly. The symbols table
is now a class with externals and weaks as separate symtabs so
the externals can be searched first then the weaks and if not
found an unresolved error is raised. This was found creating
a libbsdport RAP file where the drivers in the all driver table
resolved to the weak symbols and so linking in nothing.

Fixing the weak symbols as found in the libbsdport library
triggered a new resolver bug. The object files now contain the
resolver state and this is used to determine if an object file
has been resolved or is currently being resolved avoiding
rescursive loops with dependent object files.

The resolver trace output is a little easier to read.

1 files changed, 1 insertions, 1 deletions

diff --git a/linkers/rtems-ld.cpp b/linkers/rtems-ld.cpp
index d051b4b..cef40f9 100644
--- a/linkers/rtems-ld.cpp
+++ b/linkers/rtems-ld.cpp
@@ -170,7 +170,7 @@ main (int argc, char* argv[])
     rld::symbols::bucket undefines;
     rld::symbols::table  base_symbols;
     rld::symbols::table  symbols;
-    rld::symbols::table  undefined;
+    rld::symbols::symtab undefined;
     std::string          entry = "rtems";
     std::string          exit;
     std::string          output = "a.out";