cuneiform: Fix build against glibc 2.26
cuneiform: Fix build against glibc 2.26

Since glibc 2.26 the string.h file includes <strings.h>, which in case
of cuneiform will include the strings.h found in Kern/hhh/tigerh/h,
because of the search path order.

Fortunately for us the strings.h in cuneiform are completely unused and
no files reference or include it. I even checked various references to
types within strings.h and the only occurences are in cf_strings.h,
which is also included by other files.

Signed-off-by: aszlig <ee1aa092358634f9c53f01b5a783726c9e21b35a@nix.build>
Cc: da39a3ee5e6b4b0d3255bfef95601890afd80709@7c6f434c

NixOS/nixpkgs,SymbiFlow/nixpkgs,SymbiFlow/nixpkgs,NixOS/nixpkgs,SymbiFlow/nixpkgs,SymbiFlow/nixpkgs,SymbiFlow/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,SymbiFlow/nixpkgs,NixOS/nixpkgs,SymbiFlow/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,SymbiFlow/nixpkgs,NixOS/nixpkgs,SymbiFlow/nixpkgs,SymbiFlow/nixpkgs,NixOS/nixpkgs,SymbiFlow/nixpkgs,SymbiFlow/nixpkgs,SymbiFlow/nixpkgs