Move custom/macos* files to macos/*

Move all macOS build scripts and resources into the same directory instead of
just having the scripts in one directory and the resources in another.

macos/build-dmg.sh

@@ -0,0 +1,53 @@
+#!/bin/sh
+
+##############################################################################
+# Script to generate TuxPaint.dmg from TuxPaint.app.
+#
+# Generating a pretty DMG file programmatically is a bit of an art.  Many
+# thanks to the appdmg project for showing how:
+# (https://github.com/LinusU/node-appdmg)
+#
+
+BUNDLE=TuxPaint.app
+TEMP_DMG=temp.dmg
+TEMP_DMG_SIZE=`expr \`du -sm "$BUNDLE" | cut -f1\` \* 15 / 10`m
+FINAL_DMG=TuxPaint.dmg
+VOLNAME="Tux Paint"
+ICON="macos/tuxpaint.icns"
+BACKGROUND="macos/background.png"
+
+
+echo "   * Creating the temporary image..."
+hdiutil create "$TEMP_DMG" -ov -fs HFS+ -size "$TEMP_DMG_SIZE" -volname "$VOLNAME" \
+&& VOLUME=`hdiutil attach "$TEMP_DMG" -nobrowse -noverify -noautoopen | grep Apple_HFS | sed 's/^.*Apple_HFS[[:blank:]]*//'` \
+|| exit 1
+
+echo "   * Adding the image background..."
+mkdir "$VOLUME/.background" \
+&& tiffutil -cathidpicheck "$BACKGROUND" -out "$VOLUME/.background/background.tiff" \
+|| exit 1
+
+echo "   * Setting the folder icon..."
+cp "$ICON" "$VOLUME/.VolumeIcon.icns" \
+&& xattr -wx com.apple.FinderInfo '00 00 00 00 00 00 00 00 04 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00' "$VOLUME" \
+|| exit 1
+
+echo "   * Copying the contents..."
+ln -s "/Applications" "$VOLUME" \
+&& cp -a "$BUNDLE" "$VOLUME" \
+&& cp -a "macos/DS_Store" "$VOLUME/.DS_Store" \
+|| exit 1
+
+echo "   * Configuring the folder to open upon mount..."
+bless --folder "$VOLUME" --openfolder "$VOLUME" \
+|| exit 1
+
+echo "   * Unmounting the temporary image..."
+hdiutil detach "$VOLUME"
+
+echo "   * Creating the final image..."
+hdiutil convert "$TEMP_DMG" -ov -format "UDBZ" -imagekey "zlib-level=9" -o "$FINAL_DMG"
+
+echo "   * Deleting the temporary image..."
+rm -f "$TEMP_DMG"
+