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

tccelf.c

@@ -1575,6 +1575,10 @@ static int elf_output_file(TCCState *s1, const char *filename)
                     put_dt(dynamic, DT_SONAME, put_elf_str(dynstr, s1->soname));
                 put_dt(dynamic, DT_TEXTREL, 0);
             }
+
+            if (s1->symbolic)
+                put_dt(dynamic, DT_SYMBOLIC, 0);
+
             /* add necessary space for other entries */
             saved_dynamic_data_offset = dynamic->data_offset;
             dynamic->data_offset += sizeof(ElfW(Dyn)) * EXTRA_RELITEMS;