gcc on CentOS is too old to support isfinite.

The built-in GCC 4.1.2 version of CentOS 5.11 is GCC ten years ago, and it will not be supported until GCC 4.3.3.
The new version of PHP configure cannot detect whether the old version of gcc supports isfinite.

So if you only have the old host, but you need to compile the new version of PHP in the CentOS 5 environment
You can change all ac_have_decl in configure to 0.

Tested in PHP 7.1.7, it does work. (You can use Vim to change it all at once)

if test "x$ac_cv_have_decl_isfinite" = xyes; then :
ac_have_decl=1 #Modified to ac_have_decl=0
else
ac_have_decl=0
the fi