Add configure check for kdf.h, and include if available.

Author: ejohnstown

configure.ac

@@ -68,6 +68,7 @@ if test "x$have_wolfssl" = "xyes"; then
     LDFLAGS="$LDFLAGS $WOLFSSL_LDFLAGS"
 fi
 
+AC_CHECK_HEADERS([wolfssl/wolfcrypt/kdf.h])
 AC_CHECK_FUNCS([wc_DhSetNamedKey])
 
 # DEBUG

include/wolfengine/we_internal.h

@@ -79,7 +79,9 @@
 #include <wolfssl/wolfcrypt/ecc.h>
 #include <wolfssl/wolfcrypt/random.h>
 #include <wolfssl/wolfcrypt/pwdbased.h>
-#include <wolfssl/wolfcrypt/kdf.h>
+#ifdef HAVE_WOLFSSL_WOLFCRYPT_KDF_H
+    #include <wolfssl/wolfcrypt/kdf.h>
+#endif
 
 #include <wolfengine/we_openssl_bc.h>
 #include <wolfengine/we_logging.h>