In /usr/bin/gpg-error-config line 15:
includedir=${prefix}/include
^--------^ SC2034: includedir appears unused. Verify use (or export if used externally).


In /usr/bin/gpg-error-config line 16:
libdir=${prefix}/lib/x86_64-linux-gnu
^----^ SC2034: libdir appears unused. Verify use (or export if used externally).


In /usr/bin/gpg-error-config line 39:
    exit $1
         ^-- SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
    exit "$1"


In /usr/bin/gpg-error-config line 49:
	    optarg=`echo "$1" | sed 's/[-_a-zA-Z0-9]*=//'`
                   ^-- SC2006: Use $(...) notation instead of legacy backticked `...`.

Did you mean: 
	    optarg=$(echo "$1" | sed 's/[-_a-zA-Z0-9]*=//')


In /usr/bin/gpg-error-config line 52:
	    optarg=
            ^----^ SC2034: optarg appears unused. Verify use (or export if used externally).


In /usr/bin/gpg-error-config line 103:
echo $output
     ^-----^ SC2086: Double quote to prevent globbing and word splitting.

Did you mean: 
echo "$output"

For more information:
  https://www.shellcheck.net/wiki/SC2034 -- includedir appears unused. Verify...
  https://www.shellcheck.net/wiki/SC2086 -- Double quote to prevent globbing ...
  https://www.shellcheck.net/wiki/SC2006 -- Use $(...) notation instead of le...