[tex-k] patch to fix dvips crashes on macos with clang

[Darrin B. Jewell]

I compiled dvips on a macos system running a recent clang:

$ sw_vers
ProductName:    Mac OS X
ProductVersion: 10.12.5
BuildVersion:   16F2073

$ uname -a
Darwin Quiteria.local 16.6.0 Darwin Kernel Version 16.6.0: Fri Apr 14 16:13:31 PDT 2017; root:xnu-3789.60.24~4/RELEASE_X86_64 x86_64

$ clang --version
Apple LLVM version 8.1.0 (clang-802.0.42)
Target: x86_64-apple-darwin16.6.0
Thread model: posix

$ xcodebuild -version
Xcode 8.3.3
Build version 8E3004b

Unfortunately, dvips crashes with an abort in strcpy (__strcpy_chk)
because the clang compiler and libraries are adding extra buffer overflow
checks in the implementation of strcpy when copying into the colordat
field of struct colorpage.  Since the code treats this as a variable
length field by mallocing extra room in the struct, the easy fix is
to use the c99 syntax for specifying variable length fields in
the end of structs.

The patch below fixes the problem.

Thanks,
Darrin

*** texlive-20170524-source.dist/texk/dvipsk/color.c	2016-11-25 10:08:46.000000000 -0800
--- texlive-20170524-source/texk/dvipsk/color.c	2017-08-06 16:31:59.000000000 -0700
***************
*** 37,43 ****
     struct colorpage *next;
     integer boploc; /* we use the bop loc as a page indicator */
     char *bg;
!    char colordat[2];
  } *colorhash[COLORHASH];
  static char *cstack, *csp, *cend, *bg;
  /*
--- 37,43 ----
     struct colorpage *next;
     integer boploc; /* we use the bop loc as a page indicator */
     char *bg;
!    char colordat[];
  } *colorhash[COLORHASH];
  static char *cstack, *csp, *cend, *bg;
  /*
***************
*** 216,222 ****
        }
     } else {
        p = (struct colorpage *)mymalloc((integer)
!                   (strlen(cstack) + sizeof(struct colorpage) + MAXCOLORLEN));
        p->next = colorhash[h];
        p->boploc = pageloc;
        strcpy(p->colordat, cstack);
--- 216,222 ----
        }
     } else {
        p = (struct colorpage *)mymalloc((integer)
!                   (strlen(cstack) + sizeof(struct colorpage) + MAXCOLORLEN + 2));
        p->next = colorhash[h];
        p->boploc = pageloc;
        strcpy(p->colordat, cstack);