+ add configure check to distinguish clang from gcc to eliminate
warnings about unused command-line parameters when compiler warnings
are enabled.
+ improve behavior when updating terminfo entries which are hardlinked
by allowing for the possibility that an alias has been repurposed to
a new primary name.
+ fix some strict compiler warnings based on package scripts.
+ further fixes for configure check for working poll (Debian #676461).
+ fix some strict compiler warnings for abi6 and 64-bits.
+ use begin_va_copy/end_va_copy macros in lib_printw.c (cf: 20120303).
+ improve a limit-check in infocmp.c (Werner Fink):