[AC_LANG_COMPILER_REQUIRE()dnl
AC_LANG_CASE([C], [fp_compiler="$CC" m4_pushdef([fp_Flags], [CFLAGS])],
[C++], [fp_compiler="$CXX" m4_pushdef([fp_Flags], [CXXFLAGS])],
[AC_LANG_COMPILER_REQUIRE()dnl
AC_LANG_CASE([C], [fp_compiler="$CC" m4_pushdef([fp_Flags], [CFLAGS])],
[C++], [fp_compiler="$CXX" m4_pushdef([fp_Flags], [CXXFLAGS])],