contrib: add "contrib/scripts/nm-copr-build.sh" script

This will be the script used by our copr repositories ([1]) for building
the SRPM of NetworkManger from git.

[1] https://copr.fedorainfracloud.org/coprs/networkmanager/

contrib/scripts/nm-copr-build.sh

@@ -0,0 +1,65 @@
+#!/bin/bash
+
+# environment variables:
+# - GIT_REF: the ref that should be build. Can be "master" or a git sha.
+# - DEBUG: set to 1 to build "--with debug".
+# - NM_GIT_BUNDLE: set to a HTTP url where to fetch the nm-git-bundle-*.noarch.rpm
+#     from. Set to empty to skip it. By default, it fetches the bundle from copr.
+
+set -ex
+
+if [[ "$DEBUG" == 1 ]]; then
+    DEBUG="--with debug"
+else
+    DEBUG="--without debug"
+fi
+
+if [[ -z "$GIT_REF" ]]; then
+    echo "\$GIT_REF is not set!"
+    exit 1
+fi
+
+mkdir NetworkManager
+pushd NetworkManager
+git init .
+
+git remote add origin https://gitlab.freedesktop.org/NetworkManager/NetworkManager.git
+git remote add github https://github.com/NetworkManager/NetworkManager
+
+get_nm_git_bundle() {
+    # try to fetch the refs from nm-git-bundle.
+    #
+    # This script runs in copr infrastructure to create the SRPM.
+    # The idea is that this URL is close and downloading it is cheaper
+    # than fetching everything from upstream git.
+    if [ -z "$NM_GIT_BUNDLE" ]; then
+        if [ -n "${NM_GIT_BUNDLE+x}" ]; then
+            return 0
+        fi
+        NM_GIT_BUNDLE='https://download.copr.fedorainfracloud.org/results/networkmanager/NetworkManager-master/fedora-33-x86_64/01877051-nm-git-bundle/nm-git-bundle-20210112-123248.noarch.rpm'
+    fi
+    mkdir nm-git-bundle
+    pushd nm-git-bundle
+    curl "$NM_GIT_BUNDLE" \
+      | rpm2cpio - \
+      | cpio -idmv
+    popd
+    git remote add nm-git-bundle "$PWD/nm-git-bundle/usr/share/NetworkManager/nm-git-bundle.git"
+    git fetch nm-git-bundle
+}
+
+get_nm_git_bundle
+git fetch github
+git fetch origin
+git remote remove nm-git-bundle || true
+
+GIT_SHA="$(git show-ref --verify --hash "$GIT_REF" 2>/dev/null ||
+           git show-ref --verify --hash "refs/remotes/origin/$GIT_REF" 2>/dev/null ||
+           git rev-parse --verify "$GIT_REF^{commit}" 2>/dev/null)"
+
+git checkout -b tmp "$GIT_SHA"
+
+./contrib/fedora/rpm/build_clean.sh -g -S -w test $DEBUG -s copr
+popd
+
+mv ./NetworkManager/contrib/fedora/rpm/latest/SRPMS/* .