write floating point limit constants to 21 significant decimal places

this is enough to produce the correct value even if the constant is
interpreted as 80-bit extended precision, which matters on archs with
excess precision (FLT_EVAL_METHOD==2) under at least some
interpretations of the C standard. the shorter representations, while
correct if converted to the nominal precision at translation time,
could produce an incorrect value at extended precision, yielding
results such as (double)DBL_MAX != DBL_MAX.

include/float.h

@@ -3,10 +3,10 @@
 
 #define FLT_RADIX 2
 
-#define FLT_TRUE_MIN 1.40129846e-45F
-#define FLT_MIN 1.17549435e-38F
-#define FLT_MAX 3.40282347e+38F
-#define FLT_EPSILON 1.19209290e-07F
+#define FLT_TRUE_MIN 1.40129846432481707092e-45F
+#define FLT_MIN 1.17549435082228750797e-38F
+#define FLT_MAX 3.40282346638528859812e+38F
+#define FLT_EPSILON 1.1920928955078125e-07F
 
 #define FLT_MANT_DIG 24
 #define FLT_MIN_EXP (-125)
@@ -16,10 +16,10 @@
 #define FLT_MIN_10_EXP (-37)
 #define FLT_MAX_10_EXP 38
 
-#define DBL_TRUE_MIN 4.9406564584124654e-324
-#define DBL_MIN 2.2250738585072014e-308
-#define DBL_MAX 1.7976931348623157e+308
-#define DBL_EPSILON 2.2204460492503131e-16
+#define DBL_TRUE_MIN 4.94065645841246544177e-324
+#define DBL_MIN 2.22507385850720138309e-308
+#define DBL_MAX 1.79769313486231570815e+308
+#define DBL_EPSILON 2.22044604925031308085e-16
 
 #define DBL_MANT_DIG 53
 #define DBL_MIN_EXP (-1021)

include/math.h

@@ -349,7 +349,7 @@ long double truncl(long double);
 
 #if defined(_XOPEN_SOURCE) || defined(_BSD_SOURCE)
 #undef  MAXFLOAT
-#define MAXFLOAT        3.40282347e+38F
+#define MAXFLOAT        3.40282346638528859812e+38F
 #endif
 
 #if defined(_XOPEN_SOURCE) || defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
@@ -379,7 +379,7 @@ double      yn(int, double);
 #endif
 
 #if defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
-#define HUGE            3.40282347e+38F
+#define HUGE            3.40282346638528859812e+38F
 
 double      scalb(double, double);
 float       scalbf(float, float);