Fix building with system-installed Arrow library (round 2nd)

CMakeLists.txt

@@ -64,7 +64,7 @@ FetchContent_Declare(
   _project_options
   # Ensure anything that depends on the extracted contents will be rebuilt
   # whenever the URL changes
-  DOWNLOAD_EXTRACT_TIMESTAMP True
+  DOWNLOAD_EXTRACT_TIMESTAMP TRUE
   URL https://github.com/aminya/project_options/archive/refs/tags/v0.24.1.zip)
 FetchContent_MakeAvailable(_project_options)
 include("${_project_options_SOURCE_DIR}/Index.cmake")
@@ -131,7 +131,8 @@ project(
   HOMEPAGE_URL "https://github.com/ljishen/bitar"
   LANGUAGES CXX C)
 
-# Ensure that the PC files installed by vcpkg has the highest priority
+set(old_PKG_CONFIG_PATH "$ENV{PKG_CONFIG_PATH}")
+# Ensure that the .pc files installed by vcpkg has the highest priority
 if(NOT DEFINED CMAKE_BUILD_TYPE OR CMAKE_BUILD_TYPE MATCHES
                                    "^[Dd][Ee][Bb][Uu][Gg]$")
   prepend_path_to_env(

cmake_modules/FindArrow.cmake

@@ -29,6 +29,13 @@
 # ~~~
 
 if(NOT BITAR_BUILD_ARROW)
+  # Temporarily remove the path to the .pc files installed by vcpkg to allow
+  # looking for system-installed libraries only when we do not intend to build
+  # Arrow.
+  set(_backup_PKG_CONFIG_PATH "$ENV{PKG_CONFIG_PATH}")
+  set(ENV{PKG_CONFIG_PATH} "${old_PKG_CONFIG_PATH}")
+  set(PKG_CONFIG_USE_CMAKE_PREFIX_PATH FALSE)
+
   if(ARROW_PARQUET)
     # Since the Parquet library depends on the Arrow library, finding the
     # Parquet library will import the Arrow library as well.
@@ -63,6 +70,10 @@ if(NOT BITAR_BUILD_ARROW)
         OFF
         CACHE INTERNAL "Build the Parquet libraries")
   endif()
+
+  set(PKG_CONFIG_USE_CMAKE_PREFIX_PATH TRUE)
+  set(ENV{PKG_CONFIG_PATH} "${_backup_PKG_CONFIG_PATH}")
+  unset(_backup_PKG_CONFIG_PATH)
 endif()
 
 if(${CMAKE_FIND_PACKAGE_NAME}_FOUND AND (NOT ARROW_PARQUET OR Parquet_FOUND))
@@ -233,7 +244,7 @@ else()
     unset(_backup_CMAKE_INTERPROCEDURAL_OPTIMIZATION)
   endif()
 
-  set(Arrow_IS_BUILT True) # Arrow is built by this project
+  set(Arrow_IS_BUILT TRUE) # Arrow is built by this project
 
   set(required_vars ${${_find_package_name_lower}_POPULATED})
 

cmake_modules/Finddpdk.cmake

@@ -47,7 +47,7 @@ set_target_properties(DPDK::dpdk PROPERTIES INTERFACE_INCLUDE_DIRECTORIES
 target_compile_options(DPDK::dpdk INTERFACE ${DPDK_STATIC_CFLAGS})
 target_link_libraries(DPDK::dpdk INTERFACE ${DPDK_STATIC_LDFLAGS})
 
-set(dpdk_IS_BUILT True) # dpdk is built by this project via vcpkg
+set(dpdk_IS_BUILT TRUE) # dpdk is built by this project via vcpkg
 if(DEFINED VCPKG_INSTALLED_DIR AND DEFINED VCPKG_TARGET_TRIPLET)
   file(REAL_PATH "${DPDK_PREFIX}" dpdk_prefix_abs)
   file(REAL_PATH "${VCPKG_INSTALLED_DIR}/${VCPKG_TARGET_TRIPLET}"
@@ -56,7 +56,7 @@ if(DEFINED VCPKG_INSTALLED_DIR AND DEFINED VCPKG_TARGET_TRIPLET)
   unset(vcpkg_triplet_dir_abs)
   unset(dpdk_prefix_abs)
 else()
-  set(dpdk_IS_BUILT False)
+  set(dpdk_IS_BUILT FALSE)
 endif()
 
 # Add the OpenSSL dependency for dpdk openssl driver