very nice found !
it's yet an other time related to patents...
however the option doesn't exist anymore in mesa3d (or i didn't search at the correct place).
i found something similar, see below.
Unfortunatly, by mistake i broke my x86_64 compilation. i'm launching a build for this night.
i'll need you for tests while i've not this bug, but it will help a lot of people, for sure.
dnl
dnl potentially-infringing-but-nobody-knows-for-sure stuff
dnl
AC_ARG_ENABLE([texture-float],
[AS_HELP_STRING([--enable-texture-float],
[enable floating-point textures and renderbuffers @<:@default=disabled@:>@])],
[enable_texture_float="$enableval"],
[enable_texture_float=no]
)
if test "x$enable_texture_float" = xyes; then
AC_MSG_WARN([Floating-point textures enabled.])
AC_MSG_WARN([Please consult docs/patents.txt with your lawyer before building Mesa.])
DEFINES="$DEFINES -DTEXTURE_FLOAT_ENABLED"
fi