OSSL_PARAM helper functions.

Provide a number of functions to allow parameters to be set and
retrieved in a type safe manner.  Functions are provided for many
integral types plus double, BIGNUM, UTF8 strings and OCTET strings.

All of the integer functions will widen the parameter data as
required.  This permits a degree of malleability in the parameter
definition.  For example a type can be changed from a thirty two bit
integer to a sixty four bit one without changing application code.
Only four and eight byte integral sizes are supported here.

A pair of real functions are available for doubles.

A pair of functions is available for BIGNUMs.  These accept any sized
unsigned integer input and convert to/from a BIGNUM.

For each OCTET and UTF8 strings, four functions are defined.  This
provide get and set functionality for string and for pointers to
strings.  The latter avoiding copies but have other inherent risks.

Finally, some utility macros and functions are defined to allow
OSSL_PARAM definition arrays to be specified in a simple manner.
There are two macro and one function for most types.  The exception
being BIGNUM, for which there is one macro and one function.

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/8451)
diff --git a/test/testutil.h b/test/testutil.h
index ec2f532..7f5db60 100644
--- a/test/testutil.h
+++ b/test/testutil.h
@@ -255,7 +255,9 @@
 DECLARE_COMPARISONS(unsigned char, uchar)
 DECLARE_COMPARISONS(long, long)
 DECLARE_COMPARISONS(unsigned long, ulong)
+DECLARE_COMPARISONS(double, double)
 DECLARE_COMPARISONS(time_t, time_t)
+
 /*
  * Because this comparison uses a printf format specifier that's not
  * universally known (yet), we provide an option to not have it declared.
@@ -406,6 +408,13 @@
 # define TEST_size_t_gt(a, b) test_size_t_gt(__FILE__, __LINE__, #a, #b, a, b)
 # define TEST_size_t_ge(a, b) test_size_t_ge(__FILE__, __LINE__, #a, #b, a, b)
 
+# define TEST_double_eq(a, b) test_double_eq(__FILE__, __LINE__, #a, #b, a, b)
+# define TEST_double_ne(a, b) test_double_ne(__FILE__, __LINE__, #a, #b, a, b)
+# define TEST_double_lt(a, b) test_double_lt(__FILE__, __LINE__, #a, #b, a, b)
+# define TEST_double_le(a, b) test_double_le(__FILE__, __LINE__, #a, #b, a, b)
+# define TEST_double_gt(a, b) test_double_gt(__FILE__, __LINE__, #a, #b, a, b)
+# define TEST_double_ge(a, b) test_double_ge(__FILE__, __LINE__, #a, #b, a, b)
+
 # define TEST_time_t_eq(a, b) test_time_t_eq(__FILE__, __LINE__, #a, #b, a, b)
 # define TEST_time_t_ne(a, b) test_time_t_ne(__FILE__, __LINE__, #a, #b, a, b)
 # define TEST_time_t_lt(a, b) test_time_t_lt(__FILE__, __LINE__, #a, #b, a, b)