allow compilation of ECC w/o DER

via e.g.

```
make -j9 EXTRALIBS="../libtommath/libtommath.a " \
	CFLAGS="-DLTC_NOTHING -DLTC_MINIMAL -DLTC_MECC -DUSE_LTM \
	-DLTM_DESC -I../libtommath"
```

src/headers/tomcrypt_custom.h

@@ -622,9 +622,11 @@
    #define LTC_PKCS_8
 #endif
 
-#ifdef LTC_PKCS_8
+#if defined(LTC_PKCS_8) && defined(LTC_DER)
    #define LTC_PADDING
    #define LTC_PBES
+#else
+   #undef LTC_PKCS_8
 #endif
 
 #if defined(LTC_CLEAN_STACK)
@@ -664,7 +666,7 @@
    #error ASN.1 DER requires MPI functionality
 #endif
 
-#if (defined(LTC_MDSA) || defined(LTC_MRSA) || defined(LTC_MECC)) && !defined(LTC_DER)
+#if (defined(LTC_MDSA) || defined(LTC_MRSA)) && !defined(LTC_DER)
    #error PK requires ASN.1 DER functionality, make sure LTC_DER is enabled
 #endif
 

src/headers/tomcrypt_pk.h

@@ -312,22 +312,27 @@ int  ecc_make_key(prng_state *prng, int wprng, int keysize, ecc_key *key);
 int  ecc_make_key_ex(prng_state *prng, int wprng, ecc_key *key, const ltc_ecc_curve *cu);
 void ecc_free(ecc_key *key);
 
+#if defined(LTC_DER)
 int  ecc_export(unsigned char *out, unsigned long *outlen, int type, const ecc_key *key);
 int  ecc_import(const unsigned char *in, unsigned long inlen, ecc_key *key);
 int  ecc_import_ex(const unsigned char *in, unsigned long inlen, ecc_key *key, const ltc_ecc_curve *cu);
+#endif
 
 int ecc_ansi_x963_export(const ecc_key *key, unsigned char *out, unsigned long *outlen);
 int ecc_ansi_x963_import(const unsigned char *in, unsigned long inlen, ecc_key *key);
 int ecc_ansi_x963_import_ex(const unsigned char *in, unsigned long inlen, ecc_key *key, const ltc_ecc_curve *cu);
 
+#if defined(LTC_DER)
 int ecc_export_openssl(unsigned char *out, unsigned long *outlen, int type, const ecc_key *key);
 int ecc_import_openssl(const unsigned char *in, unsigned long inlen, ecc_key *key);
 int ecc_import_pkcs8(const unsigned char *in, unsigned long inlen, const password_ctx *pw_ctx, ecc_key *key);
 int ecc_import_x509(const unsigned char *in, unsigned long inlen, ecc_key *key);
+#endif
 
 int  ecc_shared_secret(const ecc_key *private_key, const ecc_key *public_key,
                        unsigned char *out, unsigned long *outlen);
 
+#if defined(LTC_DER)
 int  ecc_encrypt_key(const unsigned char *in,   unsigned long inlen,
                            unsigned char *out,  unsigned long *outlen,
                            prng_state *prng, int wprng, int hash,
@@ -340,6 +345,7 @@ int  ecc_decrypt_key(const unsigned char *in,  unsigned long  inlen,
 int ecc_sign_hash(const unsigned char *in,  unsigned long inlen,
                   unsigned char *out, unsigned long *outlen,
                   prng_state *prng, int wprng, const ecc_key *key);
+#endif
 
 int ecc_sign_hash_rfc7518(const unsigned char *in,  unsigned long inlen,
                           unsigned char *out, unsigned long *outlen,
@@ -350,25 +356,31 @@ int ecc_sign_hash_rfc7518_ex(const unsigned char *in,  unsigned long inlen,
                              prng_state *prng, int wprng,
                              int *recid, const ecc_key *key);
 
+#if defined(LTC_SSH)
 int ecc_sign_hash_rfc5656(const unsigned char *in,  unsigned long inlen,
                           unsigned char *out, unsigned long *outlen,
                           prng_state *prng, int wprng, const ecc_key *key);
+#endif
 
 int ecc_sign_hash_eth27(const unsigned char *in,  unsigned long inlen,
                         unsigned char *out, unsigned long *outlen,
                         prng_state *prng, int wprng, const ecc_key *key);
 
+#if defined(LTC_DER)
 int ecc_verify_hash(const unsigned char *sig,  unsigned long siglen,
                     const unsigned char *hash, unsigned long hashlen,
                     int *stat, const ecc_key *key);
+#endif
 
 int ecc_verify_hash_rfc7518(const unsigned char *sig,  unsigned long siglen,
                             const unsigned char *hash, unsigned long hashlen,
                             int *stat, const ecc_key *key);
 
+#if defined(LTC_SSH)
 int ecc_verify_hash_rfc5656(const unsigned char *sig,  unsigned long siglen,
                             const unsigned char *hash, unsigned long hashlen,
                             int *stat, const ecc_key *key);
+#endif
 
 int ecc_verify_hash_eth27(const unsigned char *sig,  unsigned long siglen,
                           const unsigned char *hash, unsigned long hashlen,

src/headers/tomcrypt_private.h

@@ -84,6 +84,7 @@ typedef int (*fn_kdf_t)(const struct password *pwd,
                               int iteration_count,  int hash_idx,
                               unsigned char *out,   unsigned long *outlen);
 
+#if defined(LTC_PBES)
 typedef struct {
    /* KDF */
    fn_kdf_t kdf;
@@ -107,6 +108,7 @@ typedef struct
    /* only used for RC2 */
    unsigned long key_bits;
 } pbes_arg;
+#endif
 
 typedef struct {
    const pbes_properties *data;
@@ -362,10 +364,12 @@ struct get_char {
 void copy_or_zeromem(const unsigned char* src, unsigned char* dest, unsigned long len, int coz);
 void password_free(struct password *pw, const struct password_ctx *ctx);
 
+#if defined(LTC_PBES)
 int pbes_decrypt(const pbes_arg  *arg, unsigned char *dec_data, unsigned long *dec_size);
 
 int pbes1_extract(const ltc_asn1_list *s, pbes_arg *res);
 int pbes2_extract(const ltc_asn1_list *s, pbes_arg *res);
+#endif
 
 int pem_decrypt(unsigned char *data, unsigned long *datalen,
                 unsigned char *key,  unsigned long keylen,
@@ -387,10 +391,14 @@ int rand_bn_upto(void *N, void *limit, prng_state *prng, int wprng);
 int pk_get_oid(enum ltc_oid_id id, const char **st);
 int pk_get_pka_id(enum ltc_oid_id id, enum ltc_pka_id *pka);
 int pk_get_oid_id(enum ltc_pka_id pka, enum ltc_oid_id *oid);
+#ifdef LTC_DER
 int pk_get_oid_from_asn1(const ltc_asn1_list *oid, enum ltc_oid_id *id);
+#endif
 int pk_oid_str_to_num(const char *OID, unsigned long *oid, unsigned long *oidlen);
 int pk_oid_num_to_str(const unsigned long *oid, unsigned long oidlen, char *OID, unsigned long *outlen);
 
+int pk_oid_cmp_with_ulong(const char *o1, const unsigned long *o2, unsigned long o2size);
+
 /* ---- DH Routines ---- */
 #ifdef LTC_MRSA
 int rsa_init(rsa_key *key);
@@ -416,7 +424,9 @@ int ecc_set_curve_from_mpis(void *a, void *b, void *prime, void *order, void *gx
 int ecc_copy_curve(const ecc_key *srckey, ecc_key *key);
 int ecc_set_curve_by_size(int size, ecc_key *key);
 int ecc_import_subject_public_key_info(const unsigned char *in, unsigned long inlen, ecc_key *key);
+#ifdef LTC_DER
 int ecc_import_pkcs8_asn1(ltc_asn1_list *alg_id, ltc_asn1_list *priv_key, ecc_key *key);
+#endif
 int ecc_import_with_curve(const unsigned char *in, unsigned long inlen, int type, ecc_key *key);
 int ecc_import_with_oid(const unsigned char *in, unsigned long inlen, unsigned long *oid, unsigned long oid_len, int type, ecc_key *key);
 
@@ -612,7 +622,6 @@ int x509_decode_subject_public_key_info(const unsigned char *in, unsigned long i
         enum ltc_oid_id algorithm, void *public_key, unsigned long *public_key_len,
         ltc_asn1_type parameters_type, ltc_asn1_list* parameters, unsigned long *parameters_len);
 
-int pk_oid_cmp_with_ulong(const char *o1, const unsigned long *o2, unsigned long o2size);
 int pk_oid_cmp_with_asn1(const char *o1, const ltc_asn1_list *o2);
 
 #endif /* LTC_DER */

src/pk/asn1/oid/pk_oid_cmp.c

@@ -2,8 +2,6 @@
 /* SPDX-License-Identifier: Unlicense */
 #include "tomcrypt_private.h"
 
-#ifdef LTC_DER
-
 /*
    Compare an OID string to an array of `unsigned long`.
    @return CRYPT_OK if equal
@@ -28,6 +26,8 @@ int pk_oid_cmp_with_ulong(const char *o1, const unsigned long *o2, unsigned long
    return CRYPT_OK;
 }
 
+#ifdef LTC_DER
+
 /*
    Compare an OID string to an OID element decoded from ASN.1.
    @return CRYPT_OK if equal

src/pk/ecc/ecc_decrypt_key.c

@@ -8,7 +8,7 @@
   ECC Crypto, Tom St Denis
 */
 
-#ifdef LTC_MECC
+#if defined(LTC_MECC) && defined(LTC_DER)
 
 /**
   Decrypt an ECC encrypted key

src/pk/ecc/ecc_encrypt_key.c

@@ -8,7 +8,7 @@
   ECC Crypto, Tom St Denis
 */
 
-#ifdef LTC_MECC
+#if defined(LTC_MECC) && defined(LTC_DER)
 
 /**
   Encrypt a symmetric key with ECC

src/pk/ecc/ecc_export.c

@@ -8,7 +8,7 @@
   ECC Crypto, Tom St Denis
 */
 
-#ifdef LTC_MECC
+#if defined(LTC_MECC) && defined(LTC_DER)
 
 /**
   Export an ECC key as a binary packet

src/pk/ecc/ecc_export_openssl.c

@@ -3,7 +3,7 @@
 
 #include "tomcrypt_private.h"
 
-#ifdef LTC_MECC
+#if defined(LTC_MECC) && defined(LTC_DER)
 
 /**
   Export an ECC key as a binary packet

src/pk/ecc/ecc_import.c

@@ -8,7 +8,7 @@
   ECC Crypto, Tom St Denis
 */
 
-#ifdef LTC_MECC
+#if defined(LTC_MECC) && defined(LTC_DER)
 
 /**
   Import an ECC key from a binary packet

src/pk/ecc/ecc_import_openssl.c

@@ -3,7 +3,7 @@
 
 #include "tomcrypt_private.h"
 
-#ifdef LTC_MECC
+#if defined(LTC_MECC) && defined(LTC_DER)
 
 static int s_ecc_import_private_with_oid(const unsigned char *in, unsigned long inlen, ecc_key *key)
 {

src/pk/ecc/ecc_import_pkcs8.c

@@ -3,7 +3,7 @@
 
 #include "tomcrypt_private.h"
 
-#ifdef LTC_MECC
+#if defined(LTC_MECC) && defined(LTC_DER)
 
 int ecc_import_pkcs8_asn1(ltc_asn1_list *alg_id, ltc_asn1_list *priv_key, ecc_key *key)
 {

src/pk/ecc/ecc_import_x509.c

@@ -2,7 +2,7 @@
 /* SPDX-License-Identifier: Unlicense */
 #include "tomcrypt_private.h"
 
-#ifdef LTC_MECC
+#if defined(LTC_MECC) && defined(LTC_DER)
 
 static int s_ecc_import_x509_with_oid(const unsigned char *in, unsigned long inlen, ecc_key *key)
 {

src/pk/ecc/ecc_recover_key.c

@@ -3,7 +3,7 @@
 
 #include "tomcrypt_private.h"
 
-#ifdef LTC_MECC
+#if defined(LTC_MECC) && defined(LTC_DER)
 
 #ifdef LTC_ECC_SHAMIR
 

src/pk/ecc/ecc_sign_hash.c

@@ -3,7 +3,7 @@
 
 #include "tomcrypt_private.h"
 
-#ifdef LTC_MECC
+#if defined(LTC_MECC) && defined(LTC_DER)
 
 /**
   Sign a message digest (ANSI X9.62 format)

src/pk/ecc/ecc_verify_hash.c

@@ -3,7 +3,7 @@
 
 #include "tomcrypt_private.h"
 
-#ifdef LTC_MECC
+#if defined(LTC_MECC) && defined(LTC_DER)
 
 /**
   @file ecc_verify_hash.c