#213 Include Solaris with operating systems using const keyword to remove compiler warnings

[Dan Anderson]

Include Solaris among the operating systems using the C "const" keyword.
Solaris-specific fix.
This removes compiler warnings and produces more-robust code.

Downstream patch trousers/patches/include_trousers_types.h.patch follows
(currently used in Oracle Solaris):

--- src/include/trousers_types.h 2010-09-10 12:50:27.000000000 -0700
+++ src/include/trousers_types.h 2012-04-23 13:53:43.275840000 -0700
@@ -118,9 +118,9 @@
BYTE *encData;
} TSS_KEY;

-#if (defined (linux) || defined (linux) || defined (SOLARIS) || defined (__GLIBC))
+#if (defined (linux) || defined (linux) || defined (__GLIBC))
#define BSD_CONST
-#elif (defined (OpenBSD) || defined (FreeBSD))
+#elif (defined (OpenBSD) || defined (FreeBSD) || defined (SOLARIS))
#define BSD_CONST const
#endif