network/opera: Miscellaneous cleanups

Note that this will likely be abandoned when the next major
    opera release is out; I don't use this, and thus I have
    little desire to keep it up to date.

network/opera/opera.SlackBuild

@@ -25,10 +25,19 @@
 
 PRGNAM=opera
 VERSION=10.10
-ARCH=${ARCH:-i386}
 BUILD=${BUILD:-1}
 TAG=${TAG:-_SBo}
 
+# Automatically determine the architecture we're building on:
+if [ -z "$ARCH" ]; then
+  case "$( uname -m )" in
+    i?86) ARCH=i386 ;;
+    arm*) ARCH=arm ;;
+    # Unless $ARCH is already set, use uname -m for all other archs:
+       *) ARCH=$( uname -m ) ;;
+  esac
+fi
+
 CWD=$(pwd)
 TMP=${TMP:-/tmp/SBo}
 PKG=$TMP/package-$PRGNAM
@@ -38,9 +47,11 @@ set -eu
 
 if [ "$ARCH" = "x86_64" ]; then
   LIBDIRSUFFIX="64"
-else
-  ARCH=i386
+elif [ "$ARCH" = "i386" ]; then
   LIBDIRSUFFIX=""
+else
+  printf "\n\n$ARCH is not supported...\n"
+  exit 1
 fi
 
 # Don't bother this - it's for easier manipulation and sed'ing later