diff --git a/releng/build-musl.sh b/releng/build-musl.sh
index 2626244..83f8706 100755
--- a/releng/build-musl.sh
+++ b/releng/build-musl.sh
@@ -1,4 +1,5 @@
 #!/bin/sh
+set -e
 CC="x86_64-pc-linux-gnu-gcc -m32" \
 AR="x86_64-pc-linux-gnu-ar" \
 RANLIB="x86_64-pc-linux-gnu-ranlib" \
diff --git a/releng/build-winxp-pthreads.sh b/releng/build-winxp-pthreads.sh
index e822fa4..a84e350 100755
--- a/releng/build-winxp-pthreads.sh
+++ b/releng/build-winxp-pthreads.sh
@@ -1,4 +1,5 @@
 #!/bin/sh
+set -e
 CC="x86_64-w64-mingw32-gcc -m32 -D_WIN32_WINNT=0x0501" \
 ../mingw-w64-v9.0.0/mingw-w64-libraries/winpthreads/configure \
     --prefix="$(realpath "$PWD/../winxp-pthreads")" \
diff --git a/releng/release.sh b/releng/release.sh
index a670357..a8e5a4a 100755
--- a/releng/release.sh
+++ b/releng/release.sh
@@ -15,7 +15,11 @@ make_musl() {
     make -C .. "$@"
 }
 
-make_musl clean
-make_musl
-make_mingw clean
-make_mingw
+if [ -f musl/bin/musl-gcc ]; then
+    make_musl clean
+    make_musl optim
+fi
+if command -v x86_64-w64-mingw32-gcc 2> /dev/null; then
+    make_mingw clean
+    make_mingw optim
+fi