mp_d2mp broken with gcc

[rajamukherji]

It looks like mp_d2mp generates an empty (zero) result (observed with gcc 15.2.1). My guess is an aliasing issue with the double * parameter. Using a union like below works fine, although their might be a better solution using frexp() or similar.

--- a/include/mp.h	2026-02-25 08:32:32.615644741 +0000
+++ b/include/mp.h	2026-02-25 08:25:58.773000000 +0000
@@ -649,7 +649,11 @@
 	   Reading it in as a uint64 makes this process
 	   endian-independent */
 
-	int_mant = *(uint64 *)(d);
+	union { uint64_t i; double d; } u;
+	u.d = *d;
+	int_mant = u.i;
+
+	//int_mant = *(uint64 *)(d);
 	exponent = ((int32)(int_mant >> 52) & 0x7ff) - 1023;
 	int_mant &= ~((uint64)(0xfff) << 52);
 	int_mant |= (uint64)(1) << 52;