diff --git a/m4/lx_check_cplex.m4 b/m4/lx_check_cplex.m4
deleted file mode 100644
--- a/m4/lx_check_cplex.m4
+++ /dev/null
@@ -1,81 +0,0 @@
-AC_DEFUN([LX_CHECK_CPLEX],
-[
-  AC_ARG_WITH([cplex],
-AS_HELP_STRING([--with-cplex@<:@=PREFIX@:>@], [search for CPLEX under PREFIX or under the default search paths if PREFIX is not given @<:@default@:>@])
-AS_HELP_STRING([--without-cplex], [disable checking for CPLEX]),
-              [], [with_cplex=yes])
-
-  AC_ARG_WITH([cplex-includedir],
-AS_HELP_STRING([--with-cplex-includedir=DIR], [search for CPLEX headers in DIR]),
-              [], [with_cplex_includedir=no])
-
-  AC_ARG_WITH([cplex-libdir],
-AS_HELP_STRING([--with-cplex-libdir=DIR], [search for CPLEX libraries in DIR]),
-              [], [with_cplex_libdir=no])
-
-  lx_cplex_found=no
-  if test x"$with_cplex" != x"no"; then
-    AC_MSG_CHECKING([for CPLEX])
-
-    if test x"$with_cplex_includedir" != x"no"; then
-      CPLEX_CFLAGS="-I$with_cplex_includedir"
-    elif test x"$with_cplex" != x"yes"; then
-      CPLEX_CFLAGS="-I$with_cplex/include"
-    elif test x"$CPLEX_INCLUDEDIR" != x; then
-      CPLEX_CFLAGS="-I$CPLEX_INCLUDEDIR"
-    fi
-
-    if test x"$with_cplex_libdir" != x"no"; then
-      CPLEX_LDFLAGS="-L$with_cplex_libdir"
-    elif test x"$with_cplex" != x"yes"; then
-      CPLEX_LDFLAGS="-L$with_cplex/lib"
-    elif test x"$CPLEX_LIBDIR" != x; then
-      CPLEX_LDFLAGS="-L$CPLEX_LIBDIR"
-    fi
-    CPLEX_LIBS="-lcplex -lm -lpthread"
-
-    lx_save_cxxflags="$CXXFLAGS"
-    lx_save_ldflags="$LDFLAGS"
-    lx_save_libs="$LIBS"
-    CXXFLAGS="$CPLEX_CFLAGS"
-    LDFLAGS="$CPLEX_LDFLAGS"
-    LIBS="$CPLEX_LIBS"
-
-    lx_cplex_test_prog='
-      extern "C" {
-      #include <ilcplex/cplex.h>
-      }
-
-      int main(int argc, char** argv)
-      {
-        CPXENVptr env = NULL;
-        return 0;
-      }'
-
-    AC_LANG_PUSH(C++)
-    AC_LINK_IFELSE([$lx_cplex_test_prog], [lx_cplex_found=yes], [lx_cplex_found=no])
-    AC_LANG_POP(C++)
-
-    CXXFLAGS="$lx_save_cxxflags"
-    LDFLAGS="$lx_save_ldflags"
-    LIBS="$lx_save_libs"
-
-    if test x"$lx_cplex_found" = x"yes"; then
-      AC_DEFINE([LEMON_HAVE_CPLEX], [1], [Define to 1 if you have CPLEX.])
-      lx_lp_found=yes
-      AC_DEFINE([LEMON_HAVE_LP], [1], [Define to 1 if you have any LP solver.])
-      lx_mip_found=yes
-      AC_DEFINE([LEMON_HAVE_MIP], [1], [Define to 1 if you have any MIP solver.])
-      AC_MSG_RESULT([yes])
-    else
-      CPLEX_CFLAGS=""
-      CPLEX_LDFLAGS=""
-      CPLEX_LIBS=""
-      AC_MSG_RESULT([no])
-    fi
-  fi
-  CPLEX_LIBS="$CPLEX_LDFLAGS $CPLEX_LIBS"
-  AC_SUBST(CPLEX_CFLAGS)
-  AC_SUBST(CPLEX_LIBS)
-  AM_CONDITIONAL([HAVE_CPLEX], [test x"$lx_cplex_found" = x"yes"])
-])