native: pick the NDK host toolchain tag by build host

The NDK names its prebuilt toolchain directory after the build host,
not the target. Hardcoding linux-x86_64 broke rsync/build.sh and
rsh/build.sh on macOS, which ships the toolchain under darwin-x86_64
(x86_64 binaries, run under Rosetta on Apple Silicon). Detect the
host with uname and fail loud on anything else.

Link: https://codeberg.org/0xlena/rsend/pulls/1

2 files changed, 26 insertions, 2 deletions

diff --git a/rsh/build.sh b/rsh/build.sh
index 88cdf9c..a3b2cad 100755
--- a/rsh/build.sh
+++ b/rsh/build.sh
@@ -21,7 +21,19 @@ if [ -z "$ndk" ] || [ ! -d "$ndk" ]; then
 	echo "rsh: Android NDK not found; set ANDROID_NDK_HOME" >&2
 	exit 1
 fi
-tc="$ndk/toolchains/llvm/prebuilt/linux-x86_64/bin"
+# NDK prebuilt toolchains are named by build host, not target. Pick the tag
+# matching this machine (macOS ships an x86_64 clang that runs under Rosetta on
+# Apple Silicon); the target ABI is selected separately below.
+case "$(uname -s)" in
+Linux)  host_tag=linux-x86_64 ;;
+Darwin) host_tag=darwin-x86_64 ;;
+*)      echo "rsh: unsupported build host $(uname -s)" >&2; exit 1 ;;
+esac
+tc="$ndk/toolchains/llvm/prebuilt/$host_tag/bin"
+if [ ! -d "$tc" ]; then
+	echo "rsh: NDK toolchain not found at $tc" >&2
+	exit 1
+fi
 
 ldflags="-s -w -buildid="
 
diff --git a/rsync/build.sh b/rsync/build.sh
index 1160e74..0a7fcda 100755
--- a/rsync/build.sh
+++ b/rsync/build.sh
@@ -17,7 +17,19 @@ if [ -z "$ndk" ] || [ ! -d "$ndk" ]; then
 	echo "rsync: Android NDK not found; set ANDROID_NDK_HOME" >&2
 	exit 1
 fi
-tc="$ndk/toolchains/llvm/prebuilt/linux-x86_64/bin"
+# NDK prebuilt toolchains are named by build host, not target. Pick the tag
+# matching this machine (macOS ships an x86_64 clang that runs under Rosetta on
+# Apple Silicon); the target ABI is selected separately below.
+case "$(uname -s)" in
+Linux)  host_tag=linux-x86_64 ;;
+Darwin) host_tag=darwin-x86_64 ;;
+*)      echo "rsync: unsupported build host $(uname -s)" >&2; exit 1 ;;
+esac
+tc="$ndk/toolchains/llvm/prebuilt/$host_tag/bin"
+if [ ! -d "$tc" ]; then
+	echo "rsync: NDK toolchain not found at $tc" >&2
+	exit 1
+fi
 
 work="$root/rsync/work"
 tarball="$root/rsync/rsync-${RSYNC_VERSION}.tar.gz"