Re-hide fmemopen.

Bug: None
Test: vcpkg install --triple=arm64-linux libconfuse
Change-Id: I799e9e108b1a39ee44be15ab1d86f54d81466eda
diff --git a/libc/include/stdio.h b/libc/include/stdio.h
index d24f6af..4912c0a 100644
--- a/libc/include/stdio.h
+++ b/libc/include/stdio.h
@@ -272,7 +272,12 @@
 int putc_unlocked(int __ch, FILE* _Nonnull __fp);
 int putchar_unlocked(int __ch);
 
+// This causes issues with a polyfill in libconfuse
+// https://github.com/android/ndk/issues/2081
+#if __ANDROID_API__ >= 23
 __nodiscard FILE* _Nullable fmemopen(void* _Nullable __buf, size_t __size, const char* _Nonnull __mode) __INTRODUCED_IN(23);
+#endif
+
 __nodiscard FILE* _Nullable open_memstream(char* _Nonnull * _Nonnull __ptr, size_t* _Nonnull __size_ptr) __INTRODUCED_IN(23);
 
 #if defined(__USE_BSD) || defined(__BIONIC__) /* Historically bionic exposed these. */