Changed IFUNC symbol generation slightly.

Fortune for memfd_secret-shim's current commit: Small blessing − 小吉

src/ifunc.h

@@ -2,10 +2,14 @@
 #define _IT_IFUNC_H
 //! ifunc helpers
 
-#if !IFUNC_PREFIX
+#if !defined(IFUNC_PREFIX)
 #define IFUNC_PREFIX _ifun__
 #endif
 
+#if !defined(IFUNC_IMPL_PREFIX)
+#define IFUNC_IMPL_PREFIX _impl__
+#endif
+
 #define _IFUNC_STR_(X) #X
 #define _IFUNC_STR(X) _IFUNC_STR_(X)
 
@@ -16,10 +20,11 @@
 
 #define _IFUNC_PREFIX(X) _IFUNC_PASTE(IFUNC_PREFIX, X)
 
-#define IFUNC_NAME(name, ver) _impl__ ## name ## __ ## ver 
+#define IFUNC_NAME(name, ver) _IFUNC_PASTE(_IFUNC_PASTE(_IFUNC_PASTE(IFUNC_IMPL_PREFIX, name), __), ver)
 #define IFUNC_IMPL(name, ver) __attribute__((copy(name))) IFUNC_NAME(name, ver)
 #define IFUNC_RESOLVER_A(attr, name)  __attribute__((returns_nonnull)) (* __attribute__(attr) _IFUNC_PREFIX(name) /*_ifun__ ## name*/ (void)) // When the ifunc resolver wants to return a function pointer that has attributes on it, the attribute inner list (e.g. `(returns_nonnull, const, nonnull)') can be provided as the first argument
 #define IFUNC_RESOLVER(name)  IFUNC_RESOLVER_A((copy(name)), name)
-#define IFUNC_DEF(name, params) name params __attribute__((__ifunc__(_IFUNC_PREFIX_S #name)))
+//TODO: Find out if changing visibility of IFUNC resolver is sound. If it is, set to hidden or internal.
+#define IFUNC_DEF(name, params) name params __attribute__((/*__visibility__("internal"),*/ __ifunc__(_IFUNC_PREFIX_S #name)))
 
 #endif /* _IT_IFUNC_H */

src/memfd_secret.c

@@ -5,6 +5,8 @@
 #include <errno.h>
 
 
+#define IFUNC_PREFIX		_$ifun__
+#define IFUNC_IMPL_PREFIX	_$impl__
 #include "ifunc.h"
 
 #include <memfd_secret.h>