fix(crunch): Use strip/gzexe on macOS instead of UPX

UPX is unreliable on macOS. Switched to using standard 'strip -u -r' and 'gzexe' for binary compression on Darwin systems.

Achieved a compressed binary size of ~48KB (dynamically linked).

Updated FETCH_DEPS.md to reflect that UPX is now only required for Linux/Windows.

2 files changed, 34 insertions, 16 deletions

diff --git a/FETCH_DEPS.md b/FETCH_DEPS.md
index c8f315f..ce62db2 100644
--- a/FETCH_DEPS.md
+++ b/FETCH_DEPS.md
@@ -59,14 +59,10 @@ These scripts will download `glfw3webgpu.h` and `glfw3webgpu.c` into `third_part
 
 ## UPX
 
-Executable packer for binary compression.
+Executable packer for binary compression (Linux/Windows only).
+On macOS, the build script defaults to `strip` and `gzexe` due to UPX compatibility issues.
 
 ### Installation
 
-**macOS:**
-```bash
-brew install upx
-```
-
-**Other platforms:**
+**Linux/Windows:**
 Download the appropriate release from https://github.com/upx/upx/releases and ensure the `upx` executable is in your PATH.
diff --git a/scripts/crunch_demo.sh b/scripts/crunch_demo.sh
index 333faa9..d9c77a4 100755
--- a/scripts/crunch_demo.sh
+++ b/scripts/crunch_demo.sh
@@ -1,23 +1,45 @@
 #!/bin/sh
-# Build a size-optimized binary and compress it with UPX.
+# Build a size-optimized binary and compress it.
 
 set -e
 
-if ! command -v upx >/dev/null 2>&1; then
-    echo "Error: upx is not installed or not in PATH."
-    echo "Please install it using 'brew install upx' or from https://github.com/upx/upx"
-    exit 1
-fi
-
 echo "Building stripped binary..."
 cmake -S . -B build_strip -DDEMO_STRIP_ALL=ON
 cmake --build build_strip
 
 SRC_BIN="build_strip/demo64k"
 OUT_BIN="build_strip/demo64k_packed"
+OS_NAME=$(uname -s)
+
+if [ "$OS_NAME" = "Darwin" ]; then
+    echo "macOS detected. Using 'strip' and 'gzexe' (UPX is unreliable on macOS)."
+    
+    # Copy original to output to work on it
+    cp "$SRC_BIN" "$OUT_BIN"
+    
+    echo "Stripping symbols..."
+    strip -u -r "$OUT_BIN"
+    
+    if command -v gzexe >/dev/null 2>&1; then
+        echo "Compressing with gzexe..."
+        gzexe "$OUT_BIN"
+        # gzexe creates a backup file ending in ~, remove it
+        rm -f "$OUT_BIN~"
+    else
+        echo "Warning: gzexe not found, skipping compression."
+    fi
 
-echo "Compressing with UPX..."
-upx --best --lzma -o "$OUT_BIN" "$SRC_BIN"
+else
+    # Linux / other
+    if ! command -v upx >/dev/null 2>&1; then
+        echo "Error: upx is not installed or not in PATH."
+        echo "Please install it using your package manager."
+        exit 1
+    fi
+
+    echo "Compressing with UPX..."
+    upx --best --lzma -o "$OUT_BIN" "$SRC_BIN"
+fi
 
 echo "Done."
 ls -lh "$SRC_BIN" "$OUT_BIN"