[gcc r14-9367] testsuite, darwin: improve check for -shared support

["François-Xavier Coudert" <fxcoudert@gcc.gnu.org>]

https://gcc.gnu.org/g:0ed6e5b4820e01fa86b48a7b1d62f752ec97ea41

commit r14-9367-g0ed6e5b4820e01fa86b48a7b1d62f752ec97ea41
Author: Francois-Xavier Coudert <fxcoudert@gcc.gnu.org>
Date:   Thu Mar 7 17:27:17 2024 +0100

    testsuite, darwin: improve check for -shared support
    
    The undefined symbols are allowed for C checks, but when
    this is run as C++, the mangled foo() symbol is still
    seen as undefined, and the testsuite thinks darwin does not
    support -shared.
    
    gcc/testsuite/ChangeLog:
    
            PR target/114233
            * lib/target-supports.exp: Fix test for C++.

Diff:
---
 gcc/testsuite/lib/target-supports.exp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gcc/testsuite/lib/target-supports.exp b/gcc/testsuite/lib/target-supports.exp
index ae33c4f1e3a..467b539b20d 100644
--- a/gcc/testsuite/lib/target-supports.exp
+++ b/gcc/testsuite/lib/target-supports.exp
@@ -1390,7 +1390,7 @@ proc check_effective_target_shared { } {
     # here to be undefined.
     set extra_flags ""
     if { [istarget *-*-darwin\[912\]*] } {
-      set extra_flags "-Wl,-U,_foo,-U,_bar"
+      set extra_flags "-Wl,-U,_foo,-U,_bar,-U,__Z3foov"
     }
     # Note that M68K has a multilib that supports -fpic but not
     # -fPIC, so we need to check both.  We test with a program that