C2x scanf %b support

ISO C2x defines scanf %b for input of binary integers (with an
optional 0b or 0B prefix).  Implement such support, along with the
corresponding SCNb* macros in <inttypes.h>.  Unlike the support for
binary integers with 0b or 0B prefix with scanf %i, this is supported
in all versions of scanf (independent of the standards mode used for
compilation), because there are no backwards compatibility concerns
(%b wasn't previously a supported format) the way there were for %i.

Tested for x86_64 and x86.

1 files changed, 5 insertions, 2 deletions

diff --git a/NEWS b/NEWS
index 7cec03cc76..709ee40e50 100644
--- a/NEWS
+++ b/NEWS
@@ -17,9 +17,12 @@ Major new features:
   wcstoull_l, wcstoimax, wcstoumax, wcstoq, wcstouq.  Similarly, the
   following functions support binary integers prefixed by 0b or 0B as
   input to the %i format: fscanf, scanf, sscanf, vscanf, vsscanf,
-  vfscanf, fwscanf, wscanf, swscanf, vfwscanf, vwscanf, vswscanf.
+  vfscanf, fwscanf, wscanf, swscanf, vfwscanf, vwscanf, vswscanf; those
+  functions also support the %b format for binary integers, with or
+  without such a prefix and independent of standards mode.
 
-* PRIb* and PRIB* macros from C2X have been added to <inttypes.h>.
+* PRIb*, PRIB* and SCNb* macros from C2X have been added to
+  <inttypes.h>.
 
 * printf-family functions now support the wN format length modifiers for
   arguments of type intN_t, int_leastN_t, uintN_t or uint_leastN_t (for