totalorder*: Fix compilation error on glibc 2.25..2.30. * m4/totalorder.m4 (gl_FUNC_TOTALORDERF): Test whether <math.h> has an incompatible declaration of totalorderf, and set REPLACE_TOTALORDERF to 1 if so. (gl_FUNC_TOTALORDER): Test whether <math.h> has an incompatible declaration of totalorder, and set REPLACE_TOTALORDER to 1 if so. (gl_FUNC_TOTALORDERL): Test whether <math.h> has an incompatible declaration of totalorderl, and set REPLACE_TOTALORDERL to 1 if so.