implement support for hiding symbols in libcrypto

- delete crypto.def and generate it from Symbols.list
- remove BIO_s_log since bss_log.c is not included on Windows
- add Windows specific symbols by crypto/crypto_win.list

crypto/crypto_win.list

@@ -0,0 +1,22 @@
+arc4random_buf
+asprintf
+explicit_bzero
+gettimeofday
+posix_close
+posix_connect
+posix_fgets
+posix_fopen
+posix_read
+posix_rename
+posix_write
+posix_perror
+posix_setsockopt
+reallocarray
+sleep
+strcasecmp
+strlcat
+strlcpy
+strndup
+timegm
+timingsafe_memcmp
+vasprintf

update.sh

@@ -146,6 +146,11 @@ for i in `awk '/SOURCES|HEADERS/ { print $3 }' crypto/Makefile.am` ; do
 done
 $CP crypto/compat/b_win.c crypto/bio
 $CP crypto/compat/ui_openssl_win.c crypto/ui
+# add the libcrypto symbol export list
+grep '^[[:alpha:]]' < $libcrypto_src/Symbols.list > crypto/crypto.sym
+echo EXPORTS > crypto/crypto.def
+grep -v BIO_s_log crypto/crypto.sym >> crypto/crypto.def
+cat crypto/crypto_win.list >> crypto/crypto.def
 
 # generate assembly crypto algorithms
 asm_src=$libcrypto_src