libm info problems

[Christopher Faylor]

I just noticed this when building cygwin:

  makeinfo -I /netrel/src/cygwin-snapshot-20060302-1/newlib/libm /netrel/src/cygwin-snapshot-20060302-1/newlib/libm/libm.texinfo
  ./targetdep.tex:184: @include `math/sisnan.def': No such file or directory.
  ./math/sldexp.def:1: Prev reference to nonexistent node `isnan' (perhaps incorrect sectioning?).
  ./common/sinfinity.def:1: Next reference to nonexistent node `isnan' (perhaps incorrect sectioning?).
  ./targetdep.tex:62: Menu reference to nonexistent node `isnan' (perhaps incorrect sectioning?).
  makeinfo: Removing output file `/cygnus/netrel/build/cygwin-snapshot-20060302-1/i686-pc-cygwin/newlib/libm/libm.info' due to errors; use --force to preserve.
  make[4]: [libm.info] Error 1 (ignored)

cgf