Rearrange rsaz

A small rearrangement so the inclusion of rsaz_exp.h would be
unconditional, but what that header defines becomes conditional.

This solves the weirdness where rsaz_exp.h gets in and out of the
dependency list for bn_exp.c, depending on the present architecture.
Reviewed-by: NRich Salz <rsalz@openssl.org>

crypto/bn/bn_exp.c

@@ -126,13 +126,7 @@
 # include <alloca.h>
 #endif
 
-#undef RSAZ_ENABLED
-#if defined(OPENSSL_BN_ASM_MONT) && \
-        (defined(__x86_64) || defined(__x86_64__) || \
-         defined(_M_AMD64) || defined(_M_X64))
-# include "rsaz_exp.h"
-# define RSAZ_ENABLED
-#endif
+#include "rsaz_exp.h"
 
 #undef SPARC_T4_MONT
 #if defined(OPENSSL_BN_ASM_MONT) && (defined(__sparc__) || defined(__sparc))

crypto/bn/rsaz_exp.c

@@ -42,6 +42,8 @@
 
 #include "rsaz_exp.h"
 
+#ifdef RSAZ_ENABLED
+
 /*
  * See crypto/bn/asm/rsaz-avx2.pl for further details.
  */
@@ -334,3 +336,11 @@ void RSAZ_512_mod_exp(BN_ULONG result[8],
 
     OPENSSL_cleanse(storage, sizeof(storage));
 }
+
+#else
+
+# if defined(PEDANTIC) || defined(__DECC) || defined(__clang__)
+static void *dummy = &dummy;
+# endif
+
+#endif

crypto/bn/rsaz_exp.h

@@ -31,7 +31,13 @@
 #ifndef RSAZ_EXP_H
 # define RSAZ_EXP_H
 
-# include <openssl/bn.h>
+# undef RSAZ_ENABLED
+# if defined(OPENSSL_BN_ASM_MONT) && \
+        (defined(__x86_64) || defined(__x86_64__) || \
+         defined(_M_AMD64) || defined(_M_X64))
+#  define RSAZ_ENABLED
+
+#  include <openssl/bn.h>
 
 void RSAZ_1024_mod_exp_avx2(BN_ULONG result[16],
                             const BN_ULONG base_norm[16],
@@ -44,4 +50,7 @@ void RSAZ_512_mod_exp(BN_ULONG result[8],
                       const BN_ULONG base_norm[8], const BN_ULONG exponent[8],
                       const BN_ULONG m_norm[8], BN_ULONG k0,
                       const BN_ULONG RR[8]);
+
+# endif
+
 #endif