[patch] rename getline to fix build with autoconf-2.62

[Michal Marek]

Hi,

autoconf-2.62 changed the AC_AIX and AC_MINIX and other extension macros
in a way that calling any of them will enable all extensions, including
_GNU_SOURCE (don't ask me why...). If you regenerate ./configure on a
linux machine with new autoconf, the build will fail in src/minicom.c
due to the internal getline() function conflicting with glibc's
getline() extension. Attached patch fixes that by renaming getline() to
mc_getline().

Michal