gant: convert comments to C style
gant: convert comments to C style

to silence warnings like

antpm/src/gant/gant.c:118:25: warning: C++ style comments are not allowed in ISO C90 [enabled by default]
    "fe00000000000000",  // get version - 255, 248, 253
                         ^
antpm/src/gant/gant.c:118:25: warning: (this will be reported only once per input file) [enabled by default]

Emacs:
 query-replace-regex
  ^\(.*?\)//\(.*\)$
  \1/* \2 */
gant: conversion to c99