Re-apply the previously backed-out commit that fixes the problem where

HUGE_VAL is not properly aligned on some architectures. The previous
fix now works because the two versions of 'math.h' (include/math.h
and lib/msun/src/math.h) have since been merged into one.

PR:	bin/43544

lib/libc/alpha/gen/infinity.c

@@ -33,4 +33,4 @@ __FBSDID("$FreeBSD$");
 #include <math.h>
 
 /* bytes for +Infinity on an Alpha (IEEE double format) */
-char __infinity[] = { 0, 0, 0, 0, 0, 0, 0xf0, 0x7f };
+const union __infinity_un __infinity = { { 0, 0, 0, 0, 0, 0, 0xf0, 0x7f } };

lib/libc/amd64/gen/infinity.c

@@ -8,4 +8,4 @@ __FBSDID("$FreeBSD$");
 #include <math.h>
 
 /* bytes for +Infinity on a 387 */
-char __infinity[] = { 0, 0, 0, 0, 0, 0, 0xf0, 0x7f };
+const union __infinity_un __infinity = { { 0, 0, 0, 0, 0, 0, 0xf0, 0x7f } };

lib/libc/i386/gen/infinity.c

@@ -8,4 +8,4 @@ __FBSDID("$FreeBSD$");
 #include <math.h>
 
 /* bytes for +Infinity on a 387 */
-char __infinity[] = { 0, 0, 0, 0, 0, 0, 0xf0, 0x7f };
+const union __infinity_un __infinity = { { 0, 0, 0, 0, 0, 0, 0xf0, 0x7f } };

lib/libc/ia64/gen/infinity.c

@@ -33,4 +33,4 @@ __FBSDID("$FreeBSD$");
 #include <math.h>
 
 /* bytes for +Infinity on an ia64 (IEEE double format) */
-char __infinity[] = { 0, 0, 0, 0, 0, 0, 0xf0, 0x7f };
+const union __infinity_un __infinity = { { 0, 0, 0, 0, 0, 0, 0xf0, 0x7f } };

lib/libc/sparc64/gen/infinity.c

@@ -11,4 +11,4 @@ __FBSDID("$FreeBSD$");
 #include <math.h>
 
 /* bytes for +Infinity on a sparc */
-char __infinity[] = { 0x7f, (char)0xf0, 0, 0, 0, 0, 0, 0 };
+const union __infinity_un __infinity = { { 0x7f, 0xf0, 0, 0, 0, 0, 0, 0 } };

lib/msun/src/math.h

@@ -20,8 +20,11 @@
 /*
  * ANSI/POSIX
  */
-extern char __infinity[];
-#define HUGE_VAL	(*(double *) __infinity)
+extern const union __infinity_un {
+	unsigned char	__uc[8];
+	double		__ud;
+} __infinity;
+#define HUGE_VAL	(__infinity.__ud)
 
 /*
  * XOPEN/SVID