Defined Endians.
Can potentially go upstream.

diff --git a/configure b/configure
--- a/configure
+++ b/configure
@@ -9620,6 +9620,18 @@
 #define SOLARIS 1
 EOF
 
+    if test "$CPU_ARCH" = "sparc"; then
+ cat >> confdefs.pytmp <<\EOF
+  (''' WORDS_BIGENDIAN ''', ' 1 ')
+  (''' IS_BIG_ENDIAN ''', ' 1 ')
+EOF
+cat >> confdefs.h <<\EOF
+#define WORDS_BIGENDIAN 1
+#define IS_BIG_ENDIAN 1
+EOF
+
+    fi
+
     TARGET_NSPR_MDCPUCFG='\"md/_solaris.cfg\"'
     MOZ_FIX_LINK_PATHS=
     # $ORIGIN/.. is for shared libraries under components/ to locate shared