Further work on aarch64 wheels

manylinux/before_all.sh

@@ -7,9 +7,11 @@ set -e -u
 package="$1"
 
 yum install -y \
-    wget libpcap libpcap-devel python-devel \
-    cmake3 ninja-build pandoc libnl3-devel \
-    ccache
+    wget libpcap libpcap-devel \
+    cmake3 ninja-build pandoc libnl3-devel
+if [[ "${CC:-}" == ccache* ]]; then
+    yum install -y ccache
+fi
 
 # Workaround for https://github.com/pypa/manylinux/issues/1203
 unset SSL_CERT_FILE

pyproject.toml

@@ -7,13 +7,21 @@ before-all = "manylinux/before_all.sh {package}"
 before-build = "manylinux/before_build.sh"
 manylinux-x86_64-image="manylinux2014"
 manylinux-i686-image="manylinux2014"
-manylinux-aarch64-image="manylinux2014"
+# The manylinux2014 AArch64 images don't provide cmake, so build 2_28 wheels instead
+manylinux-aarch64-image="manylinux_2_28"
 build = ["cp38-manylinux*", "cp39-manylinux*", "cp310-manylinux*", "cp311-manylinux*"]
 
 [tool.cibuildwheel.linux]
-archs = ["x86_64", "aarch64"]
+archs = ["aarch64", "x86_64"]
 
 [tool.cibuildwheel.linux.environment]
+CFLAGS = "-flto"
+LDFLAGS = "-flto"
+
+# ccache isn't available on all architectures, so only use it conditionally
+[[tool.cibuildwheel.overrides]]
+select = "*linux_x86_64"
+[tool.cibuildwheel.overrides.environment]
 CC = "ccache gcc"
 CFLAGS = "-flto"
 LDFLAGS = "-flto"