Add 32-bit ARM version

Dockerfile

@@ -2,6 +2,14 @@ FROM quay.io/pypa/manylinux_2_28_x86_64 as build-amd64
 
 FROM quay.io/pypa/manylinux_2_28_aarch64 as build-arm64
 
+FROM debian:bullseye as build-armv7
+
+RUN apt-get update && \
+    apt-get install --yes --no-install-recommends \
+        build-essential cmake ca-certificates curl pkg-config
+
+# -----------------------------------------------------------------------------
+
 ARG TARGETARCH
 ARG TARGETVARIANT
 FROM build-${TARGETARCH}${TARGETVARIANT} as build
@@ -46,7 +54,7 @@ RUN mkdir -p piper && \
 
 # -----------------------------------------------------------------------------
 
-FROM debian:buster as test
+FROM debian:bullseye as test
 ARG TARGETARCH
 ARG TARGETVARIANT
 

Makefile

@@ -1,4 +1,4 @@
-.PHONY: piper clean test
+.PHONY: piper clean
 
 LIB_DIR := lib/Linux-$(shell uname -m)
 
@@ -11,7 +11,4 @@ clean:
 	rm -rf build/ dist/
 
 docker:
-	docker buildx build . --platform 'linux/amd64,linux/arm64' --output 'type=local,dest=dist'
-
-test:
-	docker buildx build -f Dockerfile.test . --platform 'linux/amd64,linux/arm64'
+	docker buildx build . --platform 'linux/amd64,linux/arm64,linux/arm/v7' --output 'type=local,dest=dist'

README.md

@@ -48,8 +48,9 @@ Our goal is to support Home Assistant and the [Year of Voice](https://www.home-a
 
 Download a release:
 
-* [amd64](https://github.com/rhasspy/piper/releases/download/v1.0.0/piper_amd64.tar.gz) (desktop Linux)
-* [arm64](https://github.com/rhasspy/piper/releases/download/v1.0.0/piper_arm64.tar.gz) (Raspberry Pi 4)
+* [amd64](https://github.com/rhasspy/piper/releases/download/v1.0.0/piper_amd64.tar.gz) (64-bit desktop Linux)
+* [arm64](https://github.com/rhasspy/piper/releases/download/v1.0.0/piper_arm64.tar.gz) (64-bit Raspberry Pi 4)
+* [armv7](https://github.com/rhasspy/piper/releases/download/v1.0.0/piper_armv7.tar.gz) (32-bit Raspberry Pi 3/4)
 
 If you want to build from source, see the [Makefile](Makefile) and [C++ source](src/cpp).
 You must download and extract [piper-phonemize](https://github.com/rhasspy/piper-phonemize) to `lib/Linux-$(uname -m)/piper_phonemize` before building.