games/mame: Support optional GroovyMAME patch.

games/mame/README

@@ -18,3 +18,6 @@ Optionally, MAME can be built with a debugger for emulated ROM
 code. You don't need this just to play the games; it's mainly useful
 for developing MAME itself. To build the debugger, first install qt5,
 then set QTDEBUG=yes in the environment before building mame.
+
+Optionally, MAME can be built with the GroovyMAME patch. See
+README_groovy.txt for details.

games/mame/README_groovy.txt

@@ -0,0 +1,38 @@
+GroovyMAME, also known as GroovyUME, is a fork of MAME/UME with greater
+emphasis on CRT monitor support, in order to provide smoother gameplay
+with less input lag than using regular MAME on an LCD screen. GroovyMAME
+is provided as a patch against the standard MAME sources.
+
+GroovyMAME forum: http://forum.arcadecontrols.com/index.php?board=52.0
+
+GroovyMAME patches can be downloaded from:
+
+https://drive.google.com/drive/folders/0B5iMjDor3P__aEFpcVNkVW5jbEE
+
+Get the latest patch that matches the version of MAME. Example:
+
+0182_groovymame_017a.diff
+
+The "0182" is the MAME version, without the dots. The "017a" is the
+GroovyMAME version. You want the .diff file, not the .tar.bz2 or .7z!
+
+Download or copy the .diff file to the SlackBuild's directory and run the
+SlackBuild script. The script will find the .diff, apply it, and update
+the slack-desc to say "This package was patched with GroovyMAME 017a"
+(or whatever the version number really is). You *don't* have to do
+anything about the CRLF line endings, the script will handle that.
+
+If the script seems to be ignoring the .diff file, you probably have a
+.diff for a different version of MAME. Check the version number at the
+start of the filename. Don't try to rename the .diff file to force it
+to apply: the SlackBuild will fail because the patch will fail.
+
+If you have multiple .diff files that match the MAME version, the script
+will try to use the one with the highest GroovyMAME version number. If
+it picks the wrong one, remove the ones you don't want to use.
+
+If all else fails, please contact me by email (yalhcru@gmail.com) or on
+IRC (##slackware or #slackbuilds channel on FreeNode, user Urchlay). I
+won't necessarily be testing each MAME release against each version
+of the GroovyMAME patch for that release, so there might be problems I
+won't know about.

games/mame/mame.SlackBuild

@@ -53,9 +53,12 @@
 # 20170128 bkw:
 # - Updated for v0.182.
 
+# 20170214 bkw:
+# - Add support for GroovyMAME patch.
+
 PRGNAM=mame
 VERSION=${VERSION:-0.182}
-BUILD=${BUILD:-1}
+BUILD=${BUILD:-2}
 TAG=${TAG:-_SBo}
 
 if [ -z "$ARCH" ]; then
@@ -164,6 +167,25 @@ else
   WITHQT="without"
 fi
 
+# Now, let's check for GroovyMAME. All the user has to do is place
+# the .diff in the SlackBuild's directory. The filename always starts
+# with the MAME version number, minus its dots. If we find multiple
+# files matching this, sort them lexically and use the last (hopefully
+# this is the one with the highest version number).
+GROOVYDIFF="$( ls $CWD/${VERSION/./}_groovymame_*.diff 2>/dev/null | tail -1 )"
+if [ -e "$GROOVYDIFF" ]; then
+  GROOVYVER="$( basename $GROOVYDIFF .diff | cut -d_ -f3- | sed 's,-,_,g' )"
+
+  # .diffs are shipped with CRLF endings, fix:
+  sed 's,\r,,g' "$GROOVYDIFF" > groovy.diff
+
+  patch -p0 < groovy.diff
+
+  echo "GROOVYDIFF $GROOVYDIFF"
+  echo "GROOVYVER $GROOVYVER"
+fi
+
+
 # Having ARCH set in the env will break the build, hence ARCH=""
 
 make USE_QTDEBUG=$QTOPT \
@@ -225,6 +247,11 @@ cat $CWD/${PRGNAM}.SlackBuild > $PKG/usr/doc/${PRGNAM}-$VERSION/${PRGNAM}.SlackB
 
 mkdir -p $PKG/install
 sed "s,@WITHQT@,$WITHQT," $CWD/slack-desc > $PKG/install/slack-desc
+
+[ -n "$GROOVYVER" ] && \
+  sed -i "19s,\$, This package was patched with GroovyMAME $GROOVYVER.," \
+  $PKG/install/slack-desc
+
 cat $CWD/doinst.sh > $PKG/install/doinst.sh
 
 cd $PKG