patch 9.0.0491: no good reason to build without the float feature

Problem:    No good reason to build without the float feature.
Solution:   Remove configure check for float and "#ifdef FEAT_FLOAT".
diff --git a/src/configure.ac b/src/configure.ac
index 76eb563..b688032 100644
--- a/src/configure.ac
+++ b/src/configure.ac
@@ -3952,32 +3952,8 @@
 	AC_MSG_RESULT(yes); AC_DEFINE(HAVE_NL_LANGINFO_CODESET),
 	AC_MSG_RESULT(no))
 
-dnl Need various functions for floating point support.  Only enable
-dnl floating point when they are all present.
+dnl Floating point support may require the "m" library
 AC_CHECK_LIB(m, strtod)
-AC_MSG_CHECKING([for strtod() and other floating point functions])
-AC_LINK_IFELSE([AC_LANG_PROGRAM([
-#ifdef HAVE_MATH_H
-# include <math.h>
-#endif
-#if STDC_HEADERS
-# include <stdlib.h>
-# include <stddef.h>
-#endif
-], [char *s; double d;
-    d = strtod("1.1", &s);
-    d = fabs(1.11);
-    d = ceil(1.11);
-    d = floor(1.11);
-    d = log10(1.11);
-    d = pow(1.11, 2.22);
-    d = sqrt(1.11);
-    d = sin(1.11);
-    d = cos(1.11);
-    d = atan(1.11);
-    ])],
-	AC_MSG_RESULT(yes); AC_DEFINE(HAVE_FLOAT_FUNCS),
-	AC_MSG_RESULT(no))
 
 dnl isinf() and isnan() need to include header files and may need -lm.
 AC_MSG_CHECKING([for isinf()])