Expose a bit of lhash/conf for Ruby (aws#1987)

This extends upon aws#1986.

We do have all the necessary support for "LHASH", it's just been renamed
and made internal by upstream: b8441ac. Ruby's CONF module happens
to have a dependency on a couple of LHASH macros OpenSSL created
and the non-opaqueness of CONF.
Although we aren't likely to be supporting CONF files for the time
being, this change seems to reasonable for enough us to maintain so we
can get a better build/patch for Ruby. We still fail most CONF related
tests in Ruby, so we'll have to work around those. But this commit lets
us gracefully build with the underlying C code for Ruby CONF without any
AWS-LC specific logic.

### Testing:
Verified that this passes the build for Ruby

By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache 2.0 license and the ISC license.

crypto/conf/internal.h

@@ -26,10 +26,6 @@ extern "C" {
 
 DEFINE_LHASH_OF(CONF_VALUE)
 
-struct conf_st {
-  LHASH_OF(CONF_VALUE) *data;
-};
-
 // CONF_VALUE_new returns a freshly allocated and zeroed |CONF_VALUE|.
 CONF_VALUE *CONF_VALUE_new(void);
 

crypto/lhash/internal.h

@@ -105,7 +105,6 @@ typedef int (*lhash_cmp_func_helper)(lhash_cmp_func func, const void *a,
 typedef uint32_t (*lhash_hash_func)(const void *a);
 typedef uint32_t (*lhash_hash_func_helper)(lhash_hash_func func, const void *a);
 
-typedef struct lhash_st _LHASH;
 
 // OPENSSL_lh_new returns a new, empty hash table or NULL on error.
 OPENSSL_EXPORT _LHASH *OPENSSL_lh_new(lhash_hash_func hash,

crypto/lhash/lhash.c

@@ -347,3 +347,7 @@ void OPENSSL_lh_doall_arg(_LHASH *lh, void (*func)(void *, void *), void *arg) {
   // resizing is done here.
   lh_maybe_resize(lh);
 }
+
+void lh_doall_arg(_LHASH *lh, void (*func)(void *, void *), void *arg) {
+  OPENSSL_lh_doall_arg(lh, func, arg);
+}

include/openssl/conf.h

@@ -94,6 +94,9 @@ struct conf_value_st {
 DEFINE_STACK_OF(CONF_VALUE)
 DECLARE_LHASH_OF(CONF_VALUE)
 
+struct conf_st {
+  LHASH_OF(CONF_VALUE) *data;
+};
 
 // NCONF_new returns a fresh, empty |CONF|, or NULL on error. The |method|
 // argument must be NULL.

include/openssl/lhash.h

@@ -63,6 +63,7 @@
 extern "C" {
 #endif
 
+typedef struct lhash_st _LHASH;
 
 // lhash is an internal library and not exported for use outside BoringSSL. This
 // header is provided for compatibility with code that expects OpenSSL.
@@ -73,6 +74,18 @@ extern "C" {
 #define LHASH_OF(type) struct lhash_st_##type
 #define DECLARE_LHASH_OF(type) LHASH_OF(type);
 
+OPENSSL_EXPORT void lh_doall_arg(_LHASH *lh, void (*func)(void *, void *),
+                                 void *arg);
+
+// These two macros are the bare minimum of |LHASH| macros downstream consumers
+// use.
+#define IMPLEMENT_LHASH_DOALL_ARG_FN(name, o_type, a_type) \
+	void name##_LHASH_DOALL_ARG(void *arg1, void *arg2) { \
+		o_type *a = arg1; \
+		a_type *b = arg2; \
+		name##_doall_arg(a, b); }
+#define LHASH_DOALL_ARG_FN(name) name##_LHASH_DOALL_ARG
+
 
 #if defined(__cplusplus)
 }  // extern C