Work around Ruby on MacOS Xcode 9.4 misconfiguration defining 'isfinite'
to deprecated 'finite'. Example warning:
li_std_list_wrap.cxx:7197:9: error: 'finite' is deprecated: first deprecated in macOS 10.9 [-Werror,-Wdeprecated-declarations]
if (SWIG_Float_Overflow_Check(v)) {
^
li_std_list_wrap.cxx:7156:73: note: expanded from macro 'SWIG_Float_Overflow_Check'
^
li_std_list_wrap.cxx:7122:29: note: expanded from macro 'SWIG_isfinite'
^
/Users/travis/.rvm/rubies/ruby-2.4.3/include/ruby-2.4.0/ruby/missing.h:180:24: note: expanded from macro 'isfinite'
^
/usr/include/math.h:757:12: note: 'finite' has been explicitly marked deprecated here
extern int finite(double) __OSX_AVAILABLE_BUT_DEPRECATED(__MAC_10_0, __MAC_10_9, __IPHONE_NA, __IPHONE_NA);
PHP5 is no longer actively supported by the PHP developers and security
support for it ends completely at the end of 2018, so it doesn't make
sense to include support for it in the upcoming SWIG 4.0.0 release.
See #701.
