fix: build only liburing library, skip tests to avoid header conflicts

The liburing test suite has header conflicts between glibc and kernel headers
(redefinition of struct in6_pktinfo and ip6_mtuinfo). We only need the library
for production use, not the tests.

Changes:
- Use 'make -C src' to build only the src/ directory (library)
- Skip building test/ directory which has the header conflicts
- Still run 'make install' to install headers and library

This resolves the compilation error on manylinux containers.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: arman-bd

scripts/setup_vendors.sh

@@ -135,8 +135,9 @@ if [ "$OS" = "Linux" ]; then
     if [ ! -f "src/liburing.a" ]; then
         echo "Building liburing..."
 
+        # Build only the library, skip tests to avoid header conflicts
         ./configure --prefix="$VENDOR_DIR/liburing/install"
-        make -j$(nproc)
+        make -C src -j$(nproc)
         make install
 
         echo "✓ liburing built successfully"