Obsolete pow10 functions [committed]

[Joseph Myers]

I should add: since these functions just alias exp10 functions, it didn't 
seem worthwhile setting up testcases using compat_symbol_reference to test 
them - the tests of exp10 adequately cover that code (and the ABI tests 
verify that the functions really are present for existing ports).  So I 
just removed pow10 testing from the libm-test infrastructure and all the 
libm-test-ulps files.

-- 
Joseph S. Myers
joseph@codesourcery.com