ansi_c.nim: avoid deprecated 'expr' type
ansi_c.nim: avoid deprecated 'expr' type

tulayang/Nim,russpowers/Nim,russpowers/Nim,dom96/Nim,russpowers/Nim,tulayang/Nim,russpowers/Nim,dom96/Nim,dom96/Nim,dom96/Nim,tulayang/Nim,russpowers/Nim,dom96/Nim,tulayang/Nim,russpowers/Nim,dom96/Nim,tulayang/Nim,dom96/Nim,russpowers/Nim,tulayang/Nim