[gcc r16-847] libstdc++: Fix 17_intro/names.cc failure on Solaris 11.3

[Jonathan Wakely]

https://gcc.gnu.org/g:209353632da0e9f9600ba1c54fdfd88477fb48d0

commit r16-847-g209353632da0e9f9600ba1c54fdfd88477fb48d0
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Thu May 22 15:23:10 2025 +0100

    libstdc++: Fix 17_intro/names.cc failure on Solaris 11.3
    
    There are some names in Solaris libc headers which cause:
    
    FAIL: 17_intro/names.cc  -std=gnu++98 (test for excess errors)
    FAIL: 17_intro/names.cc  -std=gnu++11 (test for excess errors)
    
    libstdc++-v3/ChangeLog:
    
            * testsuite/17_intro/names.cc [__sun__] (a, i, n): Undefine.

Diff:
---
 libstdc++-v3/testsuite/17_intro/names.cc | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/libstdc++-v3/testsuite/17_intro/names.cc b/libstdc++-v3/testsuite/17_intro/names.cc
index f67818db425f..0e67c795564d 100644
--- a/libstdc++-v3/testsuite/17_intro/names.cc
+++ b/libstdc++-v3/testsuite/17_intro/names.cc
@@ -323,6 +323,7 @@
 
 #ifdef __sun__
 // <fenv.h> defines these as members of fex_numeric_t
+#undef i
 #undef l
 #undef f
 #undef d
@@ -332,8 +333,11 @@
 #undef ptr
 // <sys/timespec_util.h> uses this as parameter
 #undef r
-// <stdlib.h> uses this as member of drand48_data
+// <stdlib.h> uses these as members of drand48_data
+#undef a
 #undef x
+// <string.h> defines this as a parameter of timingsafe_memcmp
+#undef n
 #endif
 
 #ifdef __VXWORKS__