cmake: Only build libcrypto and libcrypto-compat when needed

This also fixes the gcrypt build.

Cherry-picked from 2f6a866373

Signed-off-by: Andreas Schneider <asn@cryptomilk.org>

src/CMakeLists.txt

@@ -124,8 +124,6 @@ set(libssh_SRCS
   kex.c
   known_hosts.c
   legacy.c
-  libcrypto.c
-  libcrypto-compat.c
   log.c
   match.c
   messages.c
@@ -164,7 +162,11 @@ else (WITH_GCRYPT)
     set(libssh_SRCS
         ${libssh_SRCS}
         pki_crypto.c
+        libcrypto.c
        )
+    if(OPENSSL_VERSION VERSION_LESS "1.1.0")
+        set(libssh_SRCS ${libssh_SRCS} libcrypto-compat.c)
+    endif()
 endif (WITH_GCRYPT)
 
 if (WITH_SFTP)

src/libcrypto-compat.c

@@ -7,9 +7,6 @@
  * https://www.openssl.org/source/license.html
  */
 
-#include <openssl/opensslv.h>
-#if OPENSSL_VERSION_NUMBER < 0x10100000L
-
 #include <string.h>
 #include <openssl/engine.h>
 #include "libcrypto-compat.h"
@@ -317,7 +314,3 @@ int HMAC_CTX_reset(HMAC_CTX *ctx)
     HMAC_CTX_init(ctx);
     return 1;
 }
-
-#else
-typedef int iso_c_forbids_an_empty_source_file;
-#endif /* OPENSSL_VERSION_NUMBER */