always use 32-bit compilation on sparc (to match what CRAN does)

Author: jjallaire

src/tbb/build/SunOS.gcc.inc

@@ -63,10 +63,13 @@ ifeq (ia32,$(arch))
     LIB_LINK_FLAGS += -m32
 endif 
 
-# for some gcc versions on Solaris, -m64 may imply V9, but perhaps not everywhere (TODO: verify)
+# for some gcc versions on Solaris, -m64 may imply V9, but perhaps not everywhere (TODO: verify).
+# RcppParallel: CRAN uses 32-bit SPARC so we force that here
 ifeq (sparc,$(arch))
-    CPLUS_FLAGS    += -mcpu=v9 -m64
-    LIB_LINK_FLAGS += -mcpu=v9 -m64
+    CPLUS_FLAGS += -m32
+    LIB_LINK_FLAGS += -m32
+#   CPLUS_FLAGS    += -mcpu=v9 -m64
+#   LIB_LINK_FLAGS += -mcpu=v9 -m64
 endif 
 
 #------------------------------------------------------------------------------