PLT calls in IFUNCs crash binaries in -Wl,-z,now mode:

https://bugs.gentoo.org/788625
--- a/lib/igt_x86.h
+++ b/lib/igt_x86.h
@@ -42,7 +42,7 @@
 #define F16C	0x200
 
 #if defined(__x86_64__) || defined(__i386__)
-unsigned igt_x86_features(void);
+unsigned igt_x86_features(void) __attribute__((visibility("hidden"))); /* Make sure we never go via PLT. */
 char *igt_x86_features_to_string(unsigned features, char *line);
 #else
 static inline unsigned igt_x86_features(void)