fix: resolve libzmq pkg-config issues in manylinux containers

- Add gcc-c++ and cmake to dependencies
- Create libzmq.pc file if missing (CentOS 7 issue)
- Set PKG_CONFIG_PATH through CIBW_ENVIRONMENT_LINUX
- Add protobuf-devel to ensure all headers are available
- Fix shell variable escaping in heredoc

.github/workflows/build-cibuildwheel.yml

@@ -54,11 +54,41 @@ jobs:
             yum clean all && yum makecache
             yum install -y epel-release || true
             yum makecache || true
-            yum install -y boost-devel protobuf-compiler zeromq-devel pkgconfig openblas-devel || echo "Some packages failed, continuing..."
+            # Install system dependencies
+            yum install -y \
+              gcc-c++ \
+              boost-devel \
+              protobuf-compiler \
+              protobuf-devel \
+              zeromq-devel \
+              pkgconfig \
+              openblas-devel \
+              cmake || echo "Some packages failed, continuing..."
+            
+            # Verify zmq installation and create pkg-config file if needed
+            if [ ! -f /usr/lib64/pkgconfig/libzmq.pc ] && [ ! -f /usr/lib/pkgconfig/libzmq.pc ]; then
+              echo "Creating libzmq.pc file..."
+              mkdir -p /usr/lib64/pkgconfig
+              cat > /usr/lib64/pkgconfig/libzmq.pc << 'EOF'
+            prefix=/usr
+            exec_prefix=${prefix}
+            libdir=${exec_prefix}/lib64
+            includedir=${prefix}/include
+            
+            Name: libzmq
+            Description: ZeroMQ library
+            Version: 4.1.4
+            Libs: -L${libdir} -lzmq
+            Cflags: -I${includedir}
+            EOF
+            fi
           
           CIBW_BEFORE_ALL_MACOS: |
             brew install llvm libomp boost protobuf zeromq
           
+          CIBW_ENVIRONMENT_LINUX: |
+            PKG_CONFIG_PATH=/usr/lib64/pkgconfig:/usr/lib/pkgconfig:$PKG_CONFIG_PATH
+          
           CIBW_ENVIRONMENT_MACOS: |
             CC=$(brew --prefix llvm)/bin/clang
             CXX=$(brew --prefix llvm)/bin/clang++
@@ -80,12 +110,22 @@ jobs:
             yum clean all && yum makecache
             yum install -y epel-release || true
             yum makecache || true
-            yum install -y protobuf-compiler openblas-devel protobuf-devel || echo "Some packages failed, continuing..."
+            # Install system dependencies for DiskANN
+            yum install -y \
+              gcc-c++ \
+              protobuf-compiler \
+              protobuf-devel \
+              openblas-devel \
+              pkgconfig \
+              cmake || echo "Some packages failed, continuing..."
             yum install -y libaio-devel || echo "libaio-devel not available, continuing..."
           
           CIBW_BEFORE_ALL_MACOS: |
             brew install llvm libomp protobuf
           
+          CIBW_ENVIRONMENT_LINUX: |
+            PKG_CONFIG_PATH=/usr/lib64/pkgconfig:/usr/lib/pkgconfig:$PKG_CONFIG_PATH
+          
           CIBW_ENVIRONMENT_MACOS: |
             CC=$(brew --prefix llvm)/bin/clang
             CXX=$(brew --prefix llvm)/bin/clang++

.github/workflows/build-reusable.yml

@@ -137,12 +137,14 @@ jobs:
           # Install development packages
           # Note: Some packages might have different names in CentOS 7
           yum install -y \
+            gcc-c++ \
             boost-devel \
             protobuf-compiler \
+            protobuf-devel \
             zeromq-devel \
             pkgconfig \
             openblas-devel \
-            protobuf-devel || {
+            cmake || {
               echo "Some packages failed to install, trying alternatives..."
               # Try alternative package names
               yum install -y libzmq3-devel || true
@@ -152,6 +154,27 @@ jobs:
           # Install optional packages that might not be available
           yum install -y libaio-devel || echo "libaio-devel not available, continuing..."
           
+          # Verify zmq installation and create pkg-config file if needed
+          if [ ! -f /usr/lib64/pkgconfig/libzmq.pc ] && [ ! -f /usr/lib/pkgconfig/libzmq.pc ]; then
+            echo "Creating libzmq.pc file..."
+            mkdir -p /usr/lib64/pkgconfig
+            cat > /usr/lib64/pkgconfig/libzmq.pc << 'EOF'
+          prefix=/usr
+          exec_prefix=${prefix}
+          libdir=${exec_prefix}/lib64
+          includedir=${prefix}/include
+          
+          Name: libzmq
+          Description: ZeroMQ library
+          Version: 4.1.4
+          Libs: -L${libdir} -lzmq
+          Cflags: -I${includedir}
+          EOF
+          fi
+          
+          # Update PKG_CONFIG_PATH
+          echo "PKG_CONFIG_PATH=/usr/lib64/pkgconfig:/usr/lib/pkgconfig:$PKG_CONFIG_PATH" >> $GITHUB_ENV
+          
           # Build tools are pre-installed in manylinux
           # MKL is more complex in container, skip for now and use OpenBLAS