Fixed a "no AC_LANG_SOURCE call detected in body" error, using instructions found here: https://www.flameeyes.eu/autotools-mythbuster/forwardporting/autoconf.html "calling macros such as ... AC_LINK_IFELSE now requires the use of AC_LANG_SOURCE or AC_LANG_PROGRAM to generate the source code to compile."
Merge branch 'master' of https://github.com/NAVADMC/SpreadModel