kconfig: assume the host libc provides POSIX reentrant functions

This change is needed to avoid including Zephyr-specific implementations
of POSIX reentrant functions while building natively. One can safely
assume that the host libc indeed provides its own implementations of
the said functions.

Signed-off-by: Ilya Tagunov <Ilya.Tagunov@synopsys.com>
diff --git a/Kconfig.zephyr b/Kconfig.zephyr
index 51ef697..5ae1273 100644
--- a/Kconfig.zephyr
+++ b/Kconfig.zephyr
@@ -448,6 +448,7 @@
 config NATIVE_LIBC
 	bool
 	select FULL_LIBC_SUPPORTED
+	select TC_PROVIDES_POSIX_C_LANG_SUPPORT_R
 	help
 	  Zephyr will use the host system C library.