android build: attempt at reproducible builds

contrib/make_packages

@@ -1,11 +1,39 @@
 #!/bin/bash
+# This script installs our pure python dependencies into the 'packages' folder.
+
+set -e
+
+CONTRIB="$(dirname "$(readlink -e "$0")")"
+PROJECT_ROOT="$CONTRIB"/..
+PACKAGES="$PROJECT_ROOT"/packages/
 
-CONTRIB="$(dirname "$0")"
 test -n "$CONTRIB" -a -d "$CONTRIB" || exit
 
-rm "$CONTRIB"/../packages/ -r
+if [ -d "$PACKAGES" ]; then
+  rm -r "$PACKAGES"
+fi
 
-#Install pure python modules in electrum directory
-python3 -m pip install --no-dependencies --no-binary :all: \
+# opt out of compiling C extensions
+# FIXME aiohttp opt-out is not released yet: https://github.com/aio-libs/aiohttp/pull/3828
+export AIOHTTP_NO_EXTENSIONS=1
+export YARL_NO_EXTENSIONS=1
+export MULTIDICT_NO_EXTENSIONS=1
+
+# if we end up having to compile something, at least give reproducibility a fighting chance
+export LC_ALL=C
+export TZ=UTC
+export SOURCE_DATE_EPOCH="$(git log -1 --pretty=%ct)"
+export PYTHONHASHSEED="$SOURCE_DATE_EPOCH"
+export BUILD_DATE="$(LC_ALL=C TZ=UTC date +'%b %e %Y' -d @$SOURCE_DATE_EPOCH)"
+export BUILD_TIME="$(LC_ALL=C TZ=UTC date +'%H:%M:%S' -d @$SOURCE_DATE_EPOCH)"
+
+# FIXME aiohttp will compile some .so files using distutils
+#       (until https://github.com/aio-libs/aiohttp/pull/4079 gets released),
+#       which are not reproducible unless using at least python 3.9
+#       (as it needs https://github.com/python/cpython/commit/0d30ae1a03102de07758650af9243fd31211325a).
+#       Hence "aiohttp-*.dist-info/" is not reproducible either.
+#       All this means that downstream users of this script, such as the sdist build
+#       and the android apk build need to make sure these files get excluded.
+python3 -m pip install --no-compile --no-dependencies --no-binary :all: \
     -r "$CONTRIB"/deterministic-build/requirements.txt -t "$CONTRIB"/../packages