Update release scripts and docs to reflect .gitattributes use.

It is no longer required to use svn-find-native-eols.pl now that
.gitattributes are in place to ensure correct EOLs in various files.

Closes #15584

build/tools/git-make-release.sh

@@ -0,0 +1,58 @@
+#!/bin/sh
+#
+# This is the official script used to make wxWidgets releases.
+#
+# We use the git export features to track which files should be included in the
+# distribution and we don't need to maintain the list of them ourselves but we
+# also don't run the risk of including anything unwanted.
+#
+# To summarize, here are the steps to create the release:
+#
+#   % git svn tag WX_x_y_z
+#   % ./build/tools/git-make-release.sh x.y.z
+#   % ... upload ../wxWidgets-x.y.z.{7z,tar.bz2,zip} ...
+
+version=$1
+if [ -z "$version" ]; then
+    echo "Must specify the distribution version." >&2
+    exit 1
+fi
+
+if ! git diff --quiet; then
+    echo "Working copy has modifications, commit or stash them." >&2
+    exit 2
+fi
+
+set -e
+set -x
+
+prefix=wxWidgets-$version
+destdir=$(dirname $(readlink -f $0))/../../../$prefix
+
+cleanup() {
+    rm -rf $destdir
+}
+
+trap cleanup INT TERM EXIT
+
+cleanup
+
+git archive --prefix=$prefix/ HEAD | (cd ..; tar x)
+cd ..
+# All setup0.h files are supposed to be renamed to just setup.h when checked
+# out and in the distribution.
+find $prefix/include/wx -type f -name setup0.h | while read f; do
+    mv $f ${f%0.h}.h
+done
+
+# Compile gettext catalogs.
+make -C $prefix/locale allmo
+
+tar cjf $prefix.tar.bz2 $prefix
+
+cd $prefix
+
+zip -q -r ../$prefix.zip .
+
+7z a ../$prefix.7z . >/dev/null
+7z a ../${prefix}_headers.7z include >/dev/null