Index: CMakeLists.txt
===================================================================
--- CMakeLists.txt
+++ CMakeLists.txt
@@ -804,7 +804,8 @@
 endif(${CMAKE_SYSTEM_NAME} MATCHES "(FreeBSD|DragonFly)")
 
 if( ${CMAKE_SYSTEM_NAME} MATCHES SunOS )
-   SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -include llvm/Support/Solaris.h")
+   # special hack for Solaris to handle crazy system sys/regset.h
+   include_directories("${LLVM_MAIN_INCLUDE_DIR}/llvm/Support/Solaris")
 endif( ${CMAKE_SYSTEM_NAME} MATCHES SunOS )
 
 # Make sure we don't get -rdynamic in every binary. For those that need it,
Index: include/llvm/Support/Host.h
===================================================================
--- include/llvm/Support/Host.h
+++ include/llvm/Support/Host.h
@@ -21,6 +21,16 @@
 #include <endian.h>
 #elif defined(_AIX)
 #include <sys/machine.h>
+#elif defined(__sun)
+/* Solaris provides _BIG_ENDIAN/_LITTLE_ENDIAN selector in sys/types.h */
+#include <sys/types.h>
+#define BIG_ENDIAN 4321
+#define LITTLE_ENDIAN 1234
+#if defined(_BIG_ENDIAN)
+#define BYTE_ORDER BIG_ENDIAN
+#else
+#define BYTE_ORDER LITTLE_ENDIAN
+#endif
 #else
 #if !defined(BYTE_ORDER) && !defined(LLVM_ON_WIN32)
 #include <machine/endian.h>
Index: include/llvm/Support/Solaris/sys/regset.h
===================================================================
--- include/llvm/Support/Solaris/sys/regset.h
+++ include/llvm/Support/Solaris/sys/regset.h
@@ -1,4 +1,4 @@
-/*===- llvm/Support/Solaris.h ------------------------------------*- C++ -*-===*
+/*===- llvm/Support/Solaris/sys/regset.h ------------------------*- C++ -*-===*
  *
  *                     The LLVM Compiler Infrastructure
  *
@@ -7,24 +7,14 @@
  *
  *===----------------------------------------------------------------------===*
  *
- * This file contains portability fixes for Solaris hosts.
+ * This file works around excessive name space pollution from the system header
+ * on Solaris hosts.
  *
  *===----------------------------------------------------------------------===*/
 
-#ifndef LLVM_SUPPORT_SOLARIS_H
-#define LLVM_SUPPORT_SOLARIS_H
+#ifndef LLVM_SUPPORT_SOLARIS_SYS_REGSET_H
 
-#include <sys/regset.h>
-#include <sys/types.h>
-
-/* Solaris doesn't have endian.h. SPARC is the only supported big-endian ISA. */
-#define BIG_ENDIAN 4321
-#define LITTLE_ENDIAN 1234
-#if defined(__sparc) || defined(__sparc__)
-#define BYTE_ORDER BIG_ENDIAN
-#else
-#define BYTE_ORDER LITTLE_ENDIAN
-#endif
+#include_next <sys/regset.h>
 
 #undef CS
 #undef DS
Index: include/llvm/module.modulemap
===================================================================
--- include/llvm/module.modulemap
+++ include/llvm/module.modulemap
@@ -275,9 +275,6 @@
     umbrella "Support"
     module * { export * }
 
-    // Exclude this; it's only included on Solaris.
-    exclude header "Support/Solaris.h"
-
     // Exclude this; it's fundamentally non-modular.
     exclude header "Support/PluginLoader.h"