Bug#848917: nautic FTBFS on architectures where char is unsigned: error: narrowing conversion of '-1' from 'int' to 'char' inside { } [-Wnarrowing]

[Adrian Bunk <bunk@stusta.de>]

Source: nautic
Version: 1.5-2
Severity: serious

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

...
g++ -DHAVE_CONFIG_H -I. -I..  -I../gnulib/lib -I../gnulib/lib -Wdate-time -D_FORTIFY_SOURCE=2 -DNDEBUG -I/usr/lib/aarch64-linux-gnu/wx/include/gtk2-unicode-3.0 -I/usr/include/wx-3.0 -D_FILE_OFFSET_BITS=64 -DWXUSINGDLL -D__WXGTK__  -g -O2 -fdebug-prefix-map=/«PKGBUILDDIR»=. -fstack-protector-strong -Wformat -Werror=format-security  -c -o main.o main.cpp
In file included from ../starpos.h:29:0,
                 from ../sun.h:36,
                 from ../stars.h:32,
                 from ../main.h:34,
                 from main.cpp:23:
../plant.h:1769:1: error: narrowing conversion of '-8' from 'int' to 'char' inside { } [-Wnarrowing]
 };
 ^
../plant.h:1769:1: error: narrowing conversion of '-5' from 'int' to 'char' inside { } [-Wnarrowing]
../plant.h:1769:1: error: narrowing conversion of '-8' from 'int' to 'char' inside { } [-Wnarrowing]
../plant.h:1769:1: error: narrowing conversion of '-5' from 'int' to 'char' inside { } [-Wnarrowing]
../plant.h:1769:1: error: narrowing conversion of '-8' from 'int' to 'char' inside { } [-Wnarrowing]
../plant.h:1769:1: error: narrowing conversion of '-7' from 'int' to 'char' inside { } [-Wnarrowing]
../plant.h:1769:1: error: narrowing conversion of '-13' from 'int' to 'char' inside { } [-Wnarrowing]
../plant.h:1769:1: error: narrowing conversion of '-1' from 'int' to 'char' inside { } [-Wnarrowing]
../plant.h:1769:1: error: narrowing conversion of '-13' from 'int' to 'char' inside { } [-Wnarrowing]
../plant.h:1769:1: error: narrowing conversion of '-2' from 'int' to 'char' inside { } [-Wnarrowing]
../plant.h:1769:1: error: narrowing conversion of '-8' from 'int' to 'char' inside { } [-Wnarrowing]
../plant.h:1769:1: error: narrowing conversion of '-10' from 'int' to 'char' inside { } [-Wnarrowing]
../plant.h:1769:1: error: narrowing conversion of '-2' from 'int' to 'char' inside { } [-Wnarrowing]
../plant.h:1769:1: error: narrowing conversion of '-3' from 'int' to 'char' inside { } [-Wnarrowing]
../plant.h:1769:1: error: narrowing conversion of '-2' from 'int' to 'char' inside { } [-Wnarrowing]
../plant.h:1769:1: error: narrowing conversion of '-6' from 'int' to 'char' inside { } [-Wnarrowing]
../plant.h:1769:1: error: narrowing conversion of '-5' from 'int' to 'char' inside { } [-Wnarrowing]
../plant.h:1769:1: error: narrowing conversion of '-15' from 'int' to 'char' inside { } [-Wnarrowing]
../plant.h:1769:1: error: narrowing conversion of '-7' from 'int' to 'char' inside { } [-Wnarrowing]
../plant.h:1769:1: error: narrowing conversion of '-3' from 'int' to 'char' inside { } [-Wnarrowing]
...