Fix MinGW32 compilation with libjpeg.

MinGW32 (or more exactly, a rpcndr.h file included by
winsock2.h) typedefs a 'boolean' type that jmorecfg.h
included by jpeglib.h also tries to typedef.
So, tell the jpeg headers.

Closes: 3007302

libvncclient/rfbproto.c

@@ -47,6 +47,9 @@
 #endif
 #endif
 #ifdef LIBVNCSERVER_HAVE_LIBJPEG
+#ifdef _RPCNDR_H /* This Windows header typedefs 'boolean', jpeglib has to know */
+#define HAVE_BOOLEAN
+#endif
 #include <jpeglib.h>
 #endif
 #include <stdarg.h>

libvncserver/tight.c

@@ -34,6 +34,9 @@
 #define NEEDFAR_POINTERS
 #endif
 
+#ifdef _RPCNDR_H /* This Windows header typedefs 'boolean', jpeglib has to know */
+#define HAVE_BOOLEAN
+#endif
 #include <jpeglib.h>
 
 /* Note: The following constant should not be changed. */