Bugfix: configure: Check for openssl/ec.h

configure.ac

@@ -678,6 +678,14 @@ else
   fi
 fi
 
+CFLAGS_TEMP="$CFLAGS"
+LIBS_TEMP="$LIBS"
+CFLAGS="$CFLAGS $SSL_CFLAGS $CRYPTO_CFLAGS"
+LIBS="$LIBS $SSL_LIBS $CRYPTO_LIBS"
+AC_CHECK_HEADER([openssl/ec.h],, AC_MSG_ERROR(OpenSSL ec header missing),)
+CFLAGS="$CFLAGS_TEMP"
+LIBS="$LIBS_TEMP"
+
 BITCOIN_QT_PATH_PROGS([PROTOC], [protoc],$protoc_bin_path)
 
 AC_MSG_CHECKING([whether to build bitcoind])