Moving -mcx16 out of CPU_CFLAGS caused the detection of ATOMIC128 to
fail, because flags have to be specified by hand in cc.compiles and
cc.links invocations (why oh why??).

Ensure that these tests enable all the instruction set extensions that
will be used to build the emulators.

Fixes: c2bf2ccb266 ("configure: move -mcx16 flag out of CPU_CFLAGS", 2024-05-24)
Reported-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 meson.build | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/meson.build b/meson.build
index bbb0f6d9bcf..4ceae98ee87 100644
--- a/meson.build
+++ b/meson.build
@@ -2831,7 +2831,7 @@ config_host_data.set('CONFIG_ATOMIC64', cc.links('''
     __atomic_exchange_n(&x, y, __ATOMIC_RELAXED);
     __atomic_fetch_add(&x, y, __ATOMIC_RELAXED);
     return 0;
-  }'''))
+  }''', args: qemu_isa_flags))
 
 has_int128_type = cc.compiles('''
   __int128_t a;
@@ -2865,7 +2865,7 @@ if has_int128_type
       __atomic_compare_exchange_n(&p[4], &p[5], p[6], 0, __ATOMIC_RELAXED, __ATOMIC_RELAXED);
       return 0;
     }'''
-  has_atomic128 = cc.links(atomic_test_128)
+  has_atomic128 = cc.links(atomic_test_128, args: qemu_isa_flags)
 
   config_host_data.set('CONFIG_ATOMIC128', has_atomic128)
 
@@ -2874,7 +2874,8 @@ if has_int128_type
     # without optimization enabled.  Try again with optimizations locally
     # enabled for the function.  See
     #   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107389
-    has_atomic128_opt = cc.links('__attribute__((optimize("O1")))' + atomic_test_128)
+    has_atomic128_opt = cc.links('__attribute__((optimize("O1")))' + atomic_test_128,
+                                 args: qemu_isa_flags)
     config_host_data.set('CONFIG_ATOMIC128_OPT', has_atomic128_opt)
 
     if not has_atomic128_opt
@@ -2885,7 +2886,7 @@ if has_int128_type
           __sync_val_compare_and_swap_16(&x, y, x);
           return 0;
         }
-      '''))
+      ''', args: qemu_isa_flags))
     endif
   endif
 endif
-- 
2.46.1