Fix SPARC assembly for 64-bit

- The test for whether or not we're building for 64-bit is '#ifdef __arch64__'.
 This appears to be correct on both Linux and Solaris.

- The test for Solaris is now '#if defined(SVR4) || defined(__SVR4) ||
defined(__svr4__)'.  GCC 3.4.0 has all three defined on Solaris 9.

- Enables assembly language clip routines.

- Fixes to make GLSL code build on Solaris.

- Update gl_SPARC_asm.py.
diff --git a/src/mesa/sparc/sparc_matrix.h b/src/mesa/sparc/sparc_matrix.h
index d74b487..f677d9b 100644
--- a/src/mesa/sparc/sparc_matrix.h
+++ b/src/mesa/sparc/sparc_matrix.h
@@ -5,7 +5,7 @@
 #ifndef _SPARC_MATRIX_H
 #define _SPARC_MATRIX_H
 
-#if (defined(__sparc_v9__) && (!defined(__linux__) || defined(__linux_sparc_64__)))
+#ifdef __arch64__
 #define LDPTR		ldx
 #define MAT_M		0x00
 #define MAT_INV		0x08