include/debug: remove duplicate 'const' declaration warning

./include/debug.h:89:55: warning: duplicate 'const' declaration specifier [-Wduplicate-decl-specifier]

Signed-off-by: Sami Kerola <kerolasa@iki.fi>
cfdisk: add missing initializers to struct main_menuitems

disk-utils/cfdisk.c:149:77: warning: missing field 'userdata' initializer [-Wmissing-field-initializers]

Signed-off-by: Sami Kerola <kerolasa@iki.fi>
findmnt: add missing initializers to struct colinfo

warning: missing field 'match' initializer [-Wmissing-field-initializers]
warning: missing field 'match_data' initializer [-Wmissing-field-initializers]

Signed-off-by: Sami Kerola <kerolasa@iki.fi>
lsblk: add missing initializers to struct colinfo

warning: missing field 'sort_type' initializer [-Wmissing-field-initializers]

Signed-off-by: Sami Kerola <kerolasa@iki.fi>
hwclock: use fabs() instead abs() when argument is double

sys-utils/hwclock.c:1219:13: warning: using integer absolute value function
      'abs' when argument is of floating point type [-Wabsolute-value]

Signed-off-by: Sami Kerola <kerolasa@iki.fi>