espeak-classic: fix build with gcc6

pkgs/applications/audio/espeak/default.nix

@@ -10,7 +10,11 @@ stdenv.mkDerivation rec {
 
   buildInputs = [ unzip portaudio ];
 
-  patchPhase = ''
+  patches = [
+    ./gcc6.patch
+  ];
+
+  prePatch = ''
     sed -e s,/bin/ln,ln,g -i src/Makefile
     sed -e 's,^CXXFLAGS=-O2,CXXFLAGS=-O2 -D PATH_ESPEAK_DATA=\\\"$(DATADIR)\\\",' -i src/Makefile
   '' + (if portaudio.api_version == 19 then ''

pkgs/applications/audio/espeak/gcc6.patch

@@ -0,0 +1,13 @@
+diff --git c/src/tr_languages.cpp i/src/tr_languages.cpp
+index ec210a5..9503f47 100755
+--- c/src/tr_languages.cpp
++++ i/src/tr_languages.cpp
+@@ -198,7 +198,7 @@ static const unsigned short chars_ignore_zwnj_hyphen[] = {
+ 	0x200d,  1, // zero width joiner
+ 	0, 0 };
+ 
+-const char string_ordinal[] = {0xc2,0xba,0};  // masculine ordinal character, UTF-8
++const char string_ordinal[] = {char(0xc2),char(0xba),0};  // masculine ordinal character, UTF-8
+ 
+ 
+ static Translator* NewTranslator(void)