Fix deprecation warnings on 0.7 (#48)

Author: ararslan

src/gamma.jl

@@ -48,7 +48,7 @@ end
 
 function digamma(x::BigFloat)
     z = BigFloat()
-    ccall((:mpfr_digamma, :libmpfr), Int32, (Ptr{BigFloat}, Ptr{BigFloat}, Int32), &z, &x, ROUNDING_MODE[])
+    ccall((:mpfr_digamma, :libmpfr), Int32, (Ref{BigFloat}, Ref{BigFloat}, Int32), z, x, ROUNDING_MODE[])
     return z
 end
 
@@ -437,7 +437,7 @@ end
 
 function zeta(x::BigFloat)
     z = BigFloat()
-    ccall((:mpfr_zeta, :libmpfr), Int32, (Ptr{BigFloat}, Ptr{BigFloat}, Int32), &z, &x, ROUNDING_MODE[])
+    ccall((:mpfr_zeta, :libmpfr), Int32, (Ref{BigFloat}, Ref{BigFloat}, Int32), z, x, ROUNDING_MODE[])
     return z
 end
 

test/runtests.jl

@@ -5,6 +5,10 @@ using Base.Test
 
 const SF = SpecialFunctions
 
+if isdefined(Base, :MathConstants) && isdefined(Base.MathConstants, :γ)
+    import Base.MathConstants: γ
+end
+
 # useful test functions for relative error, which differ from isapprox
 # in that relerrc separately looks at the real and imaginary parts
 relerr(z, x) = z == x ? 0.0 : abs(z - x) / abs(x)