Fix technical-UB uses of the preprocessor.

A recent test-compile at high warning level points out that if you
define a macro with a ... at the end of the parameter list, then every
call should at least include the comma before the variadic part. That
is, if you #define MACRO(x,y,...) then you shouldn't call MACRO(1,2)
with no comma after the 2. But that's what I had done in one of my
definitions of FUNC0 in the fiddly testcrypt system.

In a similar vein, it's a mistake to use the preprocessor 'defined'
operator when it's expanded from another macro. Adjusted the setup of
BB_OK in mpint_i.h to avoid doing that.

(Neither of these has yet caused a problem in any real compile, but
best to fix them before they do.)

mpint_i.h

@@ -59,7 +59,11 @@
 
 /* You can lower the BignumInt size by defining BIGNUM_OVERRIDE on the
  * command line to be your chosen max value of BIGNUM_INT_BITS_BITS */
-#define BB_OK(b) (!defined BIGNUM_OVERRIDE || BIGNUM_OVERRIDE >= b)
+#if defined BIGNUM_OVERRIDE
+#define BB_OK(b) ((b) <= BIGNUM_OVERRIDE)
+#else
+#define BB_OK(b) (1)
+#endif
 
 #if defined __SIZEOF_INT128__ && BB_OK(6)
 

testcrypt.c

@@ -1172,30 +1172,28 @@ static void process_line(BinarySource *in, strbuf *out)
 {
     ptrlen id = get_word(in);
 
-#define DISPATCH_COMMAND(cmd)                   \
-    if (ptrlen_eq_string(id, #cmd)) {           \
-        handle_##cmd(in, out);                  \
-        return;                                 \
-    }
+#define DISPATCH_INTERNAL(cmdname, handler) do {        \
+        if (ptrlen_eq_string(id, cmdname)) {            \
+            handler(in, out);                           \
+            return;                                     \
+        }                                               \
+    } while (0)
+
+#define DISPATCH_COMMAND(cmd) DISPATCH_INTERNAL(#cmd, handle_##cmd)
     DISPATCH_COMMAND(hello);
     DISPATCH_COMMAND(free);
     DISPATCH_COMMAND(newstring);
     DISPATCH_COMMAND(getstring);
     DISPATCH_COMMAND(mp_literal);
     DISPATCH_COMMAND(mp_dump);
+#undef DISPATCH_COMMAND
 
-#define FUNC(rettype, function, ...)            \
-    if (ptrlen_eq_string(id, #function)) {      \
-        handle_##function(in, out);             \
-        return;                                 \
-    }
-
-#define FUNC0 FUNC
-#define FUNC1 FUNC
-#define FUNC2 FUNC
-#define FUNC3 FUNC
-#define FUNC4 FUNC
-#define FUNC5 FUNC
+#define FUNC0(ret,func)           DISPATCH_INTERNAL(#func, handle_##func);
+#define FUNC1(ret,func,x)         DISPATCH_INTERNAL(#func, handle_##func);
+#define FUNC2(ret,func,x,y)       DISPATCH_INTERNAL(#func, handle_##func);
+#define FUNC3(ret,func,x,y,z)     DISPATCH_INTERNAL(#func, handle_##func);
+#define FUNC4(ret,func,x,y,z,v)   DISPATCH_INTERNAL(#func, handle_##func);
+#define FUNC5(ret,func,x,y,z,v,w) DISPATCH_INTERNAL(#func, handle_##func);
 
 #include "testcrypt.h"
 
@@ -1206,6 +1204,8 @@ static void process_line(BinarySource *in, strbuf *out)
 #undef FUNC1
 #undef FUNC0
 
+#undef DISPATCH_INTERNAL
+
     fatal_error("command '%.*s': unrecognised", PTRLEN_PRINTF(id));
 }