This fixes a compiler warning with clang:

floatscan.c:304:13: warning: absolute value function 'fabs' given an argument of type 'long double' but has parameter of type 'double' which may cause truncation of value [-Wabsolute-value].

This does change the behavior of the expression because the value is no longer rounded to double, however from my reading of the code, the rounding doesn't seem intended. However, if it is, I suggest introducing an explicit cast, to document the intent.

Dan