At some time in the past, it was possible to compile libXpm on MS Windows. The code to enable this has since fallen into disuse, but past security advisories concerning libXpm have motivated me to update the code so it can be built to target MS Windows again (tested with MinGW gcc 3.4.2)

2007-08-04  Jason Rumney  <jasonr@gnu.org>

    * src/XpmI.h [FOR_MSW]: Include simx.h instead of real X headers.

    * src/simx.h (_XFUNCPROTOBEGIN, _XFUNCPROTOEND, NO_ZPIPE): Define.
    (XAllocColor): Fix arg list in prototype.
    (bzero, close, fdopen, index, rindex, open, strdup, O_RDONLY):
    Map to W32 equivalents.

    * src/RdFToI.c [FOR_MSW]: Include fcntl.h.

*** src/XpmI.h~	2007-01-09 00:09:36.000000000 +0000
--- src/XpmI.h	2007-07-04 17:50:34.406250000 +0100
***************
*** 57,66 ****
  #ifdef sequent
  extern FILE *popen();
  #endif
! 
  #include <X11/Xos.h>
  #include <X11/Xfuncs.h>
  #include <X11/Xmd.h>
  
  #ifdef VMS
  #include <unixio.h>
--- 57,69 ----
  #ifdef sequent
  extern FILE *popen();
  #endif
! #ifdef FOR_MSW
! #include "simx.h"
! #else
  #include <X11/Xos.h>
  #include <X11/Xfuncs.h>
  #include <X11/Xmd.h>
+ #endif
  
  #ifdef VMS
  #include <unixio.h>
*** src/RdFToI.c~	2007-01-09 00:09:36.000000000 +0000
--- src/RdFToI.c	2007-08-03 23:59:11.203125000 +0100
***************
*** 44,49 ****
--- 44,53 ----
  #include <errno.h>
  #include <sys/types.h>
  #include <sys/wait.h>
+ #else
+ #ifdef FOR_MSW
+ #include <fcntl.h>
+ #endif
  #endif
  
  LFUNC(OpenReadFile, int, (char *filename, xpmData *mdata));
*** src/simx.h~	2007-01-09 00:09:36.000000000 +0000
--- src/simx.h	2007-08-04 00:58:30.437500000 +0100
***************
*** 41,46 ****
--- 41,50 ----
  
  #include "windows.h"			/* MS windows GDI types */
  
+ #define _XFUNCPROTOBEGIN
+ #define _XFUNCPROTOEND
+ #define NO_ZPIPE
+ 
  /*
   * minimal portability layer between ansi and KR C
   */
***************
*** 101,107 ****
  
  /* color related */
      FUNC(XParseColor, int, (Display *, Colormap *, char *, XColor *));
!     FUNC(XAllocColor, int, (Display *, Colormap *, XColor *));
      FUNC(XQueryColors, void, (Display *display, Colormap *colormap,
  			      XColor *xcolors, int ncolors));
      FUNC(XFreeColors, int, (Display *d, Colormap cmap,
--- 105,111 ----
  
  /* color related */
      FUNC(XParseColor, int, (Display *, Colormap *, char *, XColor *));
!     FUNC(XAllocColor, int, (Display *, Colormap, XColor *));
      FUNC(XQueryColors, void, (Display *display, Colormap *colormap,
  			      XColor *xcolors, int ncolors));
      FUNC(XFreeColors, int, (Display *d, Colormap cmap,
***************
*** 134,139 ****
--- 138,155 ----
  #undef LFUNC
  #undef FUNC
  
+ /* Some functions and constants that have non-standard names in the
+    MS library.  */
+ #define bzero(addr,sz) memset(addr, 0, sz)
+ #define close _close
+ #define fdopen _fdopen
+ #define index strchr
+ #define open _open
+ #define O_RDONLY _O_RDONLY
+ #define rindex strrchr
+ #define strdup _strdup
+ 
+ 
  #endif /* def FOR_MSW */
  
  #endif /* _SIMX_H */