libstdc++: Fix backwards logic in 17_intro/names.cc test [PR 97088]

I meant to undef the names that clash with newlib headers for newlib,
but I only undef'd them for non-newlib targets. This means they still
cause errors for newlib, and aren't tested for other targets.

This fixes the test to check those names for non-newlib targets, and to
undef them to avoid errors for newlib.

libstdc++-v3/ChangeLog:

	PR libstdc++/97088
	* testsuite/17_intro/names.cc: Fix #if condition for names used
	by newlib headers.

1 files changed, 7 insertions, 3 deletions

diff --git a/libstdc++-v3/testsuite/17_intro/names.cc b/libstdc++-v3/testsuite/17_intro/names.cc
index 805c100..aca7a8e 100644
--- a/libstdc++-v3/testsuite/17_intro/names.cc
+++ b/libstdc++-v3/testsuite/17_intro/names.cc
@@ -123,6 +123,10 @@
 #define ptr (
 #endif
 
+// This clashes with newlib so don't use it.
+# define __lockable		cannot be used as an identifier
+
+
 // Common template parameter names
 #define OutputIterator		OutputIterator is not a reserved name
 #define InputIterator		InputIterator is not a reserved name
@@ -222,9 +226,9 @@
 #undef y
 #endif
 
-#if ! __has_include(<newlib.h>)
-// newlib's <sys/cdefs.h> defines __lockable as a macro, so we can't use it.
-# define __lockable		cannot be used as an identifier
+#if __has_include(<newlib.h>)
+// newlib's <sys/cdefs.h> defines __lockable as a macro.
+#undef __lockable
 // newlib's <time.h> defines __tzrule_type with these members.
 #undef d
 #undef m