update CMakeLists.txt for fitting macOS and Linux

CMakeLists.txt

@@ -1,10 +1,5 @@
 cmake_minimum_required(VERSION 3.14)
 
-# Set CMake policies
-if(POLICY CMP0135)
-    cmake_policy(SET CMP0135 NEW)
-endif()
-
 # Project name
 project(VeloxDB)
 
@@ -20,44 +15,47 @@ endif()
 # Find the required Protobuf package
 find_package(Protobuf REQUIRED)
 
-# Specify the path to the .proto files
-set(PROTO_FILES
-        ${PROJECT_SOURCE_DIR}/protobuf/KeyValue.proto
-)
-
-# Generate .pb.cc and .pb.h files from .proto files
-protobuf_generate_cpp(PROTO_SRCS PROTO_HDRS ${PROTO_FILES})
-
-# Ensure that the generated files are placed in the protobuf directory
-set(GENERATED_PROTO_DIR ${PROJECT_SOURCE_DIR}/protobuf)
-
 # Include FetchContent module
 include(FetchContent)
 
-# Set Abseil option
-set(ABSL_PROPAGATE_CXX_STD ON)
-
 # Fetch Abseil library
 FetchContent_Declare(
         abseil
         GIT_REPOSITORY https://github.com/abseil/abseil-cpp.git
         GIT_TAG        20230802.0  # Use the latest stable release tag
+        GIT_SHALLOW    TRUE
+        GIT_PROGRESS   TRUE
+        GIT_CLONE_TIMEOUT 300      # Increase timeout as needed
         DOWNLOAD_EXTRACT_TIMESTAMP TRUE
 )
 FetchContent_MakeAvailable(abseil)
 
 # Fetch GoogleTest
 FetchContent_Declare(
         googletest
-        URL https://github.com/google/googletest/archive/refs/tags/release-1.12.1.zip
+        GIT_REPOSITORY https://github.com/google/googletest.git
+        GIT_TAG        release-1.12.1
+        GIT_SHALLOW    TRUE
+        GIT_PROGRESS   TRUE
+        GIT_CLONE_TIMEOUT 300      # Increase timeout as needed
         DOWNLOAD_EXTRACT_TIMESTAMP TRUE
 )
-set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
 FetchContent_MakeAvailable(googletest)
 
 # Enable testing
 enable_testing()
 
+# Specify the path to the .proto files
+set(PROTO_FILES
+        ${PROJECT_SOURCE_DIR}/protobuf/KeyValue.proto
+)
+
+# Generate .pb.cc and .pb.h files from .proto files
+protobuf_generate_cpp(PROTO_SRCS PROTO_HDRS ${PROTO_FILES})
+
+# Ensure that the generated files are placed in the protobuf directory
+set(GENERATED_PROTO_DIR ${PROJECT_SOURCE_DIR}/protobuf)
+
 # ---- DEFINE SHARED LIBRARY ----
 add_library(veloxdb_lib STATIC
         # kv