Output from running autoreconf:
  configure.ac:30: warning: AC_LANG_CONFTEST: no AC_LANG_SOURCE call detected in body
  ../../lib/autoconf/lang.m4:193: AC_LANG_CONFTEST is expanded from...
  ../../lib/autoconf/general.m4:2661: _AC_LINK_IFELSE is expanded from...
  ../../lib/autoconf/general.m4:2678: AC_LINK_IFELSE is expanded from...
  configure.ac:30: the top level
  configure.ac:30: warning: AC_LANG_CONFTEST: no AC_LANG_SOURCE call detected in body
  ../../lib/autoconf/lang.m4:193: AC_LANG_CONFTEST is expanded from...
  ../../lib/autoconf/general.m4:2661: _AC_LINK_IFELSE is expanded from...
  ../../lib/autoconf/general.m4:2678: AC_LINK_IFELSE is expanded from...
  ../../lib/m4sugar/m4sh.m4:639: AS_IF is expanded from...
  ../../lib/autoconf/general.m4:2661: _AC_LINK_IFELSE is expanded from...
  ../../lib/autoconf/general.m4:2678: AC_LINK_IFELSE is expanded from...
  configure.ac:30: the top level
  configure.ac:73: warning: AC_LANG_CONFTEST: no AC_LANG_SOURCE call detected in body
  ../../lib/autoconf/lang.m4:193: AC_LANG_CONFTEST is expanded from...
  ../../lib/autoconf/general.m4:2661: _AC_LINK_IFELSE is expanded from...
  ../../lib/autoconf/general.m4:2678: AC_LINK_IFELSE is expanded from...
  ../../lib/m4sugar/m4sh.m4:639: AS_IF is expanded from...
  ../../lib/autoconf/libs.m4:47: AC_SEARCH_LIBS is expanded from...
  ../../lib/m4sugar/m4sh.m4:639: AS_IF is expanded from...
  ../../lib/autoconf/headers.m4:129: _AC_CHECK_HEADER_MONGREL is expanded from...
  ../../lib/autoconf/headers.m4:67: AC_CHECK_HEADER is expanded from...
  ../../lib/m4sugar/m4sh.m4:607: AS_FOR is expanded from...
  ../../lib/autoconf/headers.m4:249: AC_CHECK_HEADERS is expanded from...
  configure.ac:73: the top level
  configure.ac:30: warning: AC_LANG_CONFTEST: no AC_LANG_SOURCE call detected in body
  ../../lib/autoconf/lang.m4:193: AC_LANG_CONFTEST is expanded from...
  ../../lib/autoconf/general.m4:2661: _AC_LINK_IFELSE is expanded from...
  ../../lib/autoconf/general.m4:2678: AC_LINK_IFELSE is expanded from...
  configure.ac:30: the top level
  configure.ac:30: warning: AC_LANG_CONFTEST: no AC_LANG_SOURCE call detected in body
  ../../lib/autoconf/lang.m4:193: AC_LANG_CONFTEST is expanded from...
  ../../lib/autoconf/general.m4:2661: _AC_LINK_IFELSE is expanded from...
  ../../lib/autoconf/general.m4:2678: AC_LINK_IFELSE is expanded from...
  ../../lib/m4sugar/m4sh.m4:639: AS_IF is expanded from...
  ../../lib/autoconf/general.m4:2661: _AC_LINK_IFELSE is expanded from...
  ../../lib/autoconf/general.m4:2678: AC_LINK_IFELSE is expanded from...
  configure.ac:30: the top level
  configure.ac:73: warning: AC_LANG_CONFTEST: no AC_LANG_SOURCE call detected in body
  ../../lib/autoconf/lang.m4:193: AC_LANG_CONFTEST is expanded from...
  ../../lib/autoconf/general.m4:2661: _AC_LINK_IFELSE is expanded from...
  ../../lib/autoconf/general.m4:2678: AC_LINK_IFELSE is expanded from...
  ../../lib/m4sugar/m4sh.m4:639: AS_IF is expanded from...
  ../../lib/autoconf/libs.m4:47: AC_SEARCH_LIBS is expanded from...
  ../../lib/m4sugar/m4sh.m4:639: AS_IF is expanded from...
  ../../lib/autoconf/headers.m4:129: _AC_CHECK_HEADER_MONGREL is expanded from...
  ../../lib/autoconf/headers.m4:67: AC_CHECK_HEADER is expanded from...
  ../../lib/m4sugar/m4sh.m4:607: AS_FOR is expanded from...
  ../../lib/autoconf/headers.m4:249: AC_CHECK_HEADERS is expanded from...
  configure.ac:73: the top level
  configure.ac:30: warning: AC_LANG_CONFTEST: no AC_LANG_SOURCE call detected in body
  ../../lib/autoconf/lang.m4:193: AC_LANG_CONFTEST is expanded from...
  ../../lib/autoconf/general.m4:2661: _AC_LINK_IFELSE is expanded from...
  ../../lib/autoconf/general.m4:2678: AC_LINK_IFELSE is expanded from...
  configure.ac:30: the top level
  configure.ac:30: warning: AC_LANG_CONFTEST: no AC_LANG_SOURCE call detected in body
  ../../lib/autoconf/lang.m4:193: AC_LANG_CONFTEST is expanded from...
  ../../lib/autoconf/general.m4:2661: _AC_LINK_IFELSE is expanded from...
  ../../lib/autoconf/general.m4:2678: AC_LINK_IFELSE is expanded from...
  ../../lib/m4sugar/m4sh.m4:639: AS_IF is expanded from...
  ../../lib/autoconf/general.m4:2661: _AC_LINK_IFELSE is expanded from...
  ../../lib/autoconf/general.m4:2678: AC_LINK_IFELSE is expanded from...
  configure.ac:30: the top level
  configure.ac:73: warning: AC_LANG_CONFTEST: no AC_LANG_SOURCE call detected in body
  ../../lib/autoconf/lang.m4:193: AC_LANG_CONFTEST is expanded from...
  ../../lib/autoconf/general.m4:2661: _AC_LINK_IFELSE is expanded from...
  ../../lib/autoconf/general.m4:2678: AC_LINK_IFELSE is expanded from...
  ../../lib/m4sugar/m4sh.m4:639: AS_IF is expanded from...
  ../../lib/autoconf/libs.m4:47: AC_SEARCH_LIBS is expanded from...
  ../../lib/m4sugar/m4sh.m4:639: AS_IF is expanded from...
  ../../lib/autoconf/headers.m4:129: _AC_CHECK_HEADER_MONGREL is expanded from...
  ../../lib/autoconf/headers.m4:67: AC_CHECK_HEADER is expanded from...
  ../../lib/m4sugar/m4sh.m4:607: AS_FOR is expanded from...
  ../../lib/autoconf/headers.m4:249: AC_CHECK_HEADERS is expanded from...
  configure.ac:73: the top level
  configure.ac:30: warning: AC_LANG_CONFTEST: no AC_LANG_SOURCE call detected in body
  ../../lib/autoconf/lang.m4:193: AC_LANG_CONFTEST is expanded from...
  ../../lib/autoconf/general.m4:2661: _AC_LINK_IFELSE is expanded from...
  ../../lib/autoconf/general.m4:2678: AC_LINK_IFELSE is expanded from...
  configure.ac:30: the top level
  configure.ac:30: warning: AC_LANG_CONFTEST: no AC_LANG_SOURCE call detected in body
  ../../lib/autoconf/lang.m4:193: AC_LANG_CONFTEST is expanded from...
  ../../lib/autoconf/general.m4:2661: _AC_LINK_IFELSE is expanded from...
  ../../lib/autoconf/general.m4:2678: AC_LINK_IFELSE is expanded from...
  ../../lib/m4sugar/m4sh.m4:639: AS_IF is expanded from...
  ../../lib/autoconf/general.m4:2661: _AC_LINK_IFELSE is expanded from...
  ../../lib/autoconf/general.m4:2678: AC_LINK_IFELSE is expanded from...
  configure.ac:30: the top level
  configure.ac:73: warning: AC_LANG_CONFTEST: no AC_LANG_SOURCE call detected in body
  ../../lib/autoconf/lang.m4:193: AC_LANG_CONFTEST is expanded from...
  ../../lib/autoconf/general.m4:2661: _AC_LINK_IFELSE is expanded from...
  ../../lib/autoconf/general.m4:2678: AC_LINK_IFELSE is expanded from...
  ../../lib/m4sugar/m4sh.m4:639: AS_IF is expanded from...
  ../../lib/autoconf/libs.m4:47: AC_SEARCH_LIBS is expanded from...
  ../../lib/m4sugar/m4sh.m4:639: AS_IF is expanded from...
  ../../lib/autoconf/headers.m4:129: _AC_CHECK_HEADER_MONGREL is expanded from...
  ../../lib/autoconf/headers.m4:67: AC_CHECK_HEADER is expanded from...
  ../../lib/m4sugar/m4sh.m4:607: AS_FOR is expanded from...
  ../../lib/autoconf/headers.m4:249: AC_CHECK_HEADERS is expanded from...
  configure.ac:73: the top level