The attached patch fixes the INLINE macro so it also gets set properly when using the Sun Studio compiler.  It basically adds the __SUNPRO_C part:

#if defined(__GNUC__)
#define INLINE __inline__
#elif defined (__SUNPRO_C)
#define INLINE inline
#else
#define INLINE
#endif

It would be nice if this could go upstream so that Sun Studio also compiles cairo with inline properly.

I notice that there is some mess with how inline is handled in cairo/pixman/src.  The macro is defined in icint.h and fbpict.h.  Since fbpict.h indirectly includes icint.h, this causes the macro to be defined twice.  The macro is defined separately in pixregion.c.

Also it seems some code uses "__inline" when it would be more consistent to use the INLINE macro.  

The attached patch defines INLINE just once in icint.h and adds an "#include "icint.h" to pixregion.c to access this macro.

Note that the function fbmmx.c also uses __inline and could probably be made to just use INLINE.  Since I'm not building this code, I didn't make this change since I can't test it.  If so, then this code could be removed from icint.h

#ifndef __GNUC__
#define __inline
#endif

I'm not sure my attached patch is the best approach.  Perhaps the macro should be moved to a more general header file rather than in icint.h.  Perhaps pixman.h?  But this patch shows the issues and how to approach fixing them.