It's not necessary to include any changes to awkgram.c or command.c
in patches (when *.y respective files were patched), since these
files are automatically generated by bison.
* gawk-4.2.0-000-do-not-fold-constant-strings.patch added,
to prevent some newly found regression:
http://lists.gnu.org/archive/html/bug-gawk/2017-10/msg00033.html
* enabled BuildRequires for bison because of patch above
* gawk-4.2.0-001-rwarray-small-improvements.patch added