Recognize -Wl,-Bsymbolic

Without -Bsymbolic, a symbol/function in a *.so can be overridden
by a symbol/function in the main module.
That is the default search order, but not supported by tcc.

With -Bsymbolic, the linker tries to resolve a symbol/function in
the current module first.
The loader in tcc implements this search order.

We do not distinguish -Bsymbolic and -Bsymbolic-function

--
By by ... Detlef

tcc.h

@@ -445,6 +445,9 @@ struct TCCState {
     /* if true, all symbols are exported */
     int rdynamic;
 
+    /* if true, resolve symbols in the current module first (-Wl,Bsymbolic) */
+    int symbolic;
+
     /* if true, only link in referenced objects from archive */
     int alacarte_link;