Cygwin: don't export arc4random_addrandom/arc4random_stir

Keep the functions for backward compatibility, but don't export
them from libcygwin.a for new applications.  Drop the workaround
from commit ad29c33 ("Cygwin: stdlib.h: revert declaring
arc4random_stir() as function").

Fixes: ad29c33 ("Cygwin: stdlib.h: revert declaring arc4random_stir() as function")
Signed-off-by: Corinna Vinschen <[email protected]>

Author: github-cygwin

winsup/cygwin/Makefile.am

@@ -459,6 +459,8 @@ VERSION_OFILES = version.o winver.o
 #
 
 NEW_FUNCTIONS=$(addprefix --replace=,\
+	arc4random_addrandom= \
+	arc4random_stir= \
 	atexit= \
 	timezone= \
 	uname=uname_x \

winsup/cygwin/include/cygwin/stdlib.h

@@ -20,11 +20,6 @@ extern "C"
 const char *getprogname (void);
 void	setprogname (const char *);
 
-#if __BSD_VISIBLE
-/* Cygwin exports arc4random_stir() for backward compatibility.
-   Keep the declaration compatible with libbsd. */
-void arc4random_stir(void);
-#endif
 #if __GNU_VISIBLE
 char *canonicalize_file_name (const char *);
 #endif