system/oss: Misc automated cleanups.

Signed-off-by: David Somero <xgizzmo@slackbuilds.org>

system/oss/oss.SlackBuild

@@ -7,13 +7,22 @@
 PRGNAM=oss
 VERSION=${VERSION:-4.2}
 SUBVERSION=${SUBVERSION:-2002}
-ARCH=${ARCH:-i486}
 BUILD=${BUILD:-1}
 TAG=${TAG:-_SBo}
 
 SRCVERSION=v${VERSION}-build${SUBVERSION}-src-gpl
 PKGVERSION=${VERSION}.${SUBVERSION}
 
+# Automatically determine the architecture we're building on:
+if [ -z "$ARCH" ]; then
+  case "$( uname -m )" in
+    i?86) ARCH=i486 ;;
+    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
@@ -28,6 +37,9 @@ elif [ "$ARCH" = "i686" ]; then
 elif [ "$ARCH" = "x86_64" ]; then
   SLKCFLAGS="-O2" # yes, -fPIC is left out on purpose here
   LIBDIRSUFFIX="64"
+else
+  SLKCFLAGS="-O2"
+  LIBDIRSUFFIX=""
 fi
 
 set -e # Exit on most errors