enca: fix compiler warnings for GCC with -Wunused-but-set-variable

[heitbaum]

Variable 'map_created' in xtable() is only used in assert() which is compiled out when -DNDEBUG is defined. Wrap the block in #ifndef NDEBUG to preserve debug-build sanity checking while silencing the warning in release builds.

[Syed-Shahrukh-OSSRevival]

Thank you for your contribution, makes sense.
You can utilize DEBUG.

changelog entry

2003-06-24  David Necas (Yeti) <yeti@physics.muni.cz>
    * lib/internal.h: added enca_csname macro and #include <stdio.h> when
      DEBUG is defined

[heitbaum]

Thank you for your contribution, makes sense. You can utilize DEBUG.

changelog entry

2003-06-24  David Necas (Yeti) <yeti@physics.muni.cz>
    * lib/internal.h: added enca_csname macro and #include <stdio.h> when
      DEBUG is defined

I don’t think this is the right logic. -DNDEBUG does not define -DDEBUG. They are completely separate and unrelated macros. -DNDEBUG defines the macro NDEBUG that disables assert() statements, in the C standard.

So the release build (which defines -DNDEBUG) would just treat the #ifdef as a noop. But when compiling without -DNDEBUG the assert would not activate (as it should along with the other asserts throughout the code.)

[Syed-Shahrukh-OSSRevival]

Thank you @heitbaum for your help, you are correct!

Adding the missing part for completion.

Reproduce:

./configure  CFLAGS="-DNDEBUG"

gcc -DHAVE_CONFIG_H -I. -I..  -DEXTCONV_DIR=\"/usr/local/libexec/enca/extconv\"   -Wall -Wextra -W -pedantic -DNDEBUG -MT enca-convert.o -MD -MP -MF .deps/enca-convert.Tpo -c -o enca-convert.o `test -f 'convert.c' || echo './'`convert.c
convert.c: In function ‘xtable’:
convert.c:504:11: warning: variable ‘map_created’ set but not used [-Wunused-but-set-variable]
  504 |       int map_created;
      |           ^~~~~~~~~~~
convert.c:529:9: warning: variable ‘map_created’ set but not used [-Wunused-but-set-variable]
  529 |     int map_created;
      |         ^~~~~~~~~~~

merging the PR 👍