From https://github.com/mpruett/audiofile/pull/28/commits/28cfdbbcb96a69087c3d21faf69b5eae7bcf6d69?diff=split:
GCC-6 now treats the left bitwise-shift of a negative integer as nonconformant so explicitly cast to an unsigned int while bit-shifting.

--- audiofile-audiofile-0.3.6/libaudiofile/modules/SimpleModule.h.orig	2016-11-21 15:34:50.330151685 -0200
+++ audiofile-audiofile-0.3.6/libaudiofile/modules/SimpleModule.h	2016-11-21 15:35:13.399152118 -0200
@@ -123,7 +123,7 @@ struct signConverter
 	typedef typename IntTypes<Format>::UnsignedType UnsignedType;
 
 	static const int kScaleBits = (Format + 1) * CHAR_BIT - 1;
-	static const int kMinSignedValue = -1 << kScaleBits;
+	static const int kMinSignedValue = static_cast<signed>(static_cast<unsigned>(-1) << kScaleBits);
 
 	struct signedToUnsigned : public std::unary_function<SignedType, UnsignedType>
 	{