Bug#856904: ksirk FTBFS on architectures where char is unsigned

[Adrian Bunk <bunk@debian.org>]

Source: ksirk
Version: 4:16.04.0-1
Severity: serious

https://buildd.debian.org/status/package.php?p=ksirk&suite=sid

...
/«PKGBUILDDIR»/ksirk/iris/src/xmpp/base64/base64.cpp:65:2: error: narrowing conversion of '-1' from 'int' to 'char' inside { } [-Wnarrowing]
/«PKGBUILDDIR»/ksirk/iris/src/xmpp/base64/base64.cpp:65:2: error: narrowing conversion of '-1' from 'int' to 'char' inside { } [-Wnarrowing]
/«PKGBUILDDIR»/ksirk/iris/src/xmpp/base64/base64.cpp:65:2: error: narrowing conversion of '-1' from 'int' to 'char' inside { } [-Wnarrowing]
/«PKGBUILDDIR»/ksirk/iris/src/xmpp/base64/base64.cpp:65:2: error: narrowing conversion of '-1' from 'int' to 'char' inside { } [-Wnarrowing]
/«PKGBUILDDIR»/ksirk/iris/src/xmpp/base64/base64.cpp:65:2: error: narrowing conversion of '-1' from 'int' to 'char' inside { } [-Wnarrowing]
/«PKGBUILDDIR»/ksirk/iris/src/xmpp/base64/base64.cpp:65:2: error: narrowing conversion of '-1' from 'int' to 'char' inside { } [-Wnarrowing]
/«PKGBUILDDIR»/ksirk/iris/src/xmpp/base64/base64.cpp:65:2: error: narrowing conversion of '-1' from 'int' to 'char' inside { } [-Wnarrowing]
/«PKGBUILDDIR»/ksirk/iris/src/xmpp/base64/base64.cpp:65:2: error: narrowing conversion of '-1' from 'int' to 'char' inside { } [-Wnarrowing]
/«PKGBUILDDIR»/ksirk/iris/src/xmpp/base64/base64.cpp:65:2: error: narrowing conversion of '-1' from 'int' to 'char' inside { } [-Wnarrowing]
/«PKGBUILDDIR»/ksirk/iris/src/xmpp/base64/base64.cpp:65:2: error: narrowing conversion of '-1' from 'int' to 'char' inside { } [-Wnarrowing]
/«PKGBUILDDIR»/ksirk/iris/src/xmpp/base64/base64.cpp:65:2: error: narrowing conversion of '-1' from 'int' to 'char' inside { } [-Wnarrowing]
/«PKGBUILDDIR»/ksirk/iris/src/xmpp/base64/base64.cpp:65:2: error: narrowing conversion of '-1' from 'int' to 'char' inside { } [-Wnarrowing]
...