謎エラー

configure.in:14: warning: AC_CACHE_VAL(lt_prog_compiler_pic_works, ...): suspicious cache-id, must contain _cv_ to be cached
../../lib/autoconf/general.m4:1973: AC_CACHE_VAL is expanded from...
../../lib/autoconf/general.m4:1993: AC_CACHE_CHECK is expanded from...
/usr/share/aclocal/libtool.m4:615: AC_LIBTOOL_COMPILER_OPTION is expanded from...
/usr/share/aclocal/libtool.m4:4815: AC_LIBTOOL_PROG_COMPILER_PIC is expanded from...
/usr/share/aclocal/libtool.m4:2651: _LT_AC_LANG_C_CONFIG is expanded from...
/usr/share/aclocal/libtool.m4:2650: AC_LIBTOOL_LANG_C_CONFIG is expanded from...
/usr/share/aclocal/libtool.m4:80: AC_LIBTOOL_SETUP is expanded from...
/usr/share/aclocal/libtool.m4:60: _AC_PROG_LIBTOOL is expanded from...
/usr/share/aclocal/libtool.m4:25: AC_PROG_LIBTOOL is expanded from...
configure.in:14: the top level
configure.in:14: warning: AC_CACHE_VAL(lt_prog_compiler_static_works, ...): suspicious cache-id, must contain _cv_ to be cached
/usr/share/aclocal/libtool.m4:660: AC_LIBTOOL_LINKER_OPTION is expanded from...
以下略

こんなかんじでAC_PROG_LIBTOOLでエラーが出て困っていたのですが、automakeを再インストールすると解決しました。MacPortsでautotoolsを入れているとたまに遭遇するらしい。