readelf: Display the base symbol version as empty string

readelf: Display the base symbol version as empty string

Update readelf to display the base symbol version as

Symbol table for image contains 5 entries:
   Num:    Value          Size Type    Bind   Vis      Ndx Name
     0: 0000000000000000     0 NOTYPE  LOCAL  DEFAULT  UND
     1: 0000000000003008     0 OBJECT  GLOBAL DEFAULT   10 bar@@
     2: 0000000000000000     0 OBJECT  GLOBAL DEFAULT  ABS VERS_1
     3: 0000000000003008     0 OBJECT  GLOBAL DEFAULT   10 bar@@VERS_1
     4: 0000000000003000     0 OBJECT  GLOBAL DEFAULT   10 foo@

instead of

Symbol table for image contains 5 entries:
   Num:    Value          Size Type    Bind   Vis      Ndx Name
     0: 0000000000000000     0 NOTYPE  LOCAL  DEFAULT  UND
     1: 0000000000003008     0 OBJECT  GLOBAL DEFAULT   10 bar
     2: 0000000000000000     0 OBJECT  GLOBAL DEFAULT  ABS VERS_1
     3: 0000000000003008     0 OBJECT  GLOBAL DEFAULT   10 bar@@VERS_1
     4: 0000000000003000     0 OBJECT  GLOBAL DEFAULT   10 foo

That is bar@@ and foo@ vs bar and foo.

binutils/

	PR binutils/33599
	* readelf.c (process_version_sections): Replace 0x8001 with
	(VERSYM_HIDDEN | VERSYM_BASE).
	(get_symbol_version_string): Likewise.  Return "" for the base
	version.

include/

	PR binutils/33599
	* elf/common.h (VERSYM_BASE): New.

ld/

	PR binutils/33599
	* testsuite/ld-elf/pr33599.d: New file.
	* testsuite/ld-elf/pr33599.map: Likewise.
	* testsuite/ld-elf/pr33599.s: Likewise.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>