See http://johannes.sipsolutions.net/N810

--- kernel-source-rx-34-2.6.21.0/crypto/api.c	2007-04-26 05:08:32.000000000 +0200
+++ build-rx-34-2.6.21.0/crypto/api.c	2008-02-29 00:36:12.000000000 +0100
@@ -434,3 +434,5 @@
 	return ret;
 }
 EXPORT_SYMBOL_GPL(crypto_has_alg);
+
+MODULE_LICENSE("GPL");
--- kernel-source-rx-34-2.6.21.0/crypto/Kconfig	2008-02-18 20:25:32.000000000 +0100
+++ build-rx-34-2.6.21.0/crypto/Kconfig	2008-02-29 00:27:32.000000000 +0100
@@ -5,7 +5,7 @@
 menu "Cryptographic options"
 
 config CRYPTO
-	bool "Cryptographic API"
+	tristate "Cryptographic API"
 	help
 	  This option provides the core Cryptographic API.
 
--- kernel-source-rx-34-2.6.21.0/crypto/Makefile	2008-02-18 20:25:32.000000000 +0100
+++ build-rx-34-2.6.21.0/crypto/Makefile	2008-02-29 00:32:47.000000000 +0100
@@ -2,7 +2,8 @@
 # Cryptographic API
 #
 
-obj-$(CONFIG_CRYPTO) += api.o scatterwalk.o cipher.o digest.o compress.o
+crypto-objs := api.o scatterwalk.o cipher.o digest.o compress.o
+obj-$(CONFIG_CRYPTO) += crypto.o
 
 crypto_algapi-$(CONFIG_PROC_FS) += proc.o
 crypto_algapi-objs := algapi.o $(crypto_algapi-y)
--- kernel-source-rx-34-2.6.21.0/include/linux/crypto.h	2007-04-26 05:08:32.000000000 +0200
+++ build-rx-34-2.6.21.0/include/linux/crypto.h	2008-02-29 00:30:57.000000000 +0100
@@ -217,7 +217,7 @@
 /*
  * Algorithm query interface.
  */
-#ifdef CONFIG_CRYPTO
+#if defined(CONFIG_CRYPTO) || (defined(CONFIG_CRYPTO_MODULE) && defined(MODULE))
 int crypto_has_alg(const char *name, u32 type, u32 mask);
 #else
 static inline int crypto_has_alg(const char *name, u32 type, u32 mask)