add new package: redir (#772)

add new package: redir (#772)

* add bvi package

* add new package: cgdb

* add gdb in cgdb's TERMUX_PKG_DEPENDS

* add new package: redir

* bvi package revision 1: fix column number issue with clang (gcc does not seem to have this issue)
bvi (compiled with clang) incorrectly displayed only 12 bytes for each line on a 80-column terminal (instead of 16 bytes normally). command :set cm=## also had similar problems.
I found the issue was caused by the following statements:
       sprintf(addr_form,  "%%0%dllX  ", AnzAdd);
       AnzAdd = sprintf(tmp, addr_form, block_begin);

	   ('block_begin''s data type is off_t)
	   gcc automatically typecasts 'block_begin' from off_t to loff_t,
	   on the otherhand, clang takes address of 'block_begin' and uses
	   it as loff_t thus writes some garbage value in 'tmp' string.