Allow cloning external projects from local repos

CMakeLists.txt

@@ -38,6 +38,16 @@ option(PREFER_SYSTEM_XXHASH "use system xxHash if available" OFF)
 option(PREFER_SYSTEM_GTEST "use system gtest if available" OFF)
 option(STATIC_BUILD_DO_NOT_USE "try static build (experimental)" OFF)
 
+if(DEFINED ENV{DWARFS_LOCAL_REPO_PATH})
+  set(LIBFMT_GIT_REPO $ENV{DWARFS_LOCAL_REPO_PATH}/fmt)
+  set(GOOGLETEST_GIT_REPO $ENV{DWARFS_LOCAL_REPO_PATH}/googletest)
+  set(LIBARCHIVE_GIT_REPO $ENV{DWARFS_LOCAL_REPO_PATH}/libarchive)
+else()
+  set(LIBFMT_GIT_REPO https://github.com/fmtlib/fmt.git)
+  set(GOOGLETEST_GIT_REPO https://github.com/google/googletest.git)
+  set(LIBARCHIVE_GIT_REPO https://github.com/libarchive/libarchive.git)
+endif()
+
 set(default_build_type "Release")
 
 set(CMAKE_CXX_STANDARD 20)
@@ -765,7 +775,7 @@ if(STATIC_BUILD_DO_NOT_USE)
   ExternalProject_Add(
     ${_LIBARCHIVE_PRJ}
     PREFIX "${PROJECT_BINARY_DIR}/libarchive"
-    GIT_REPOSITORY "https://github.com/libarchive/libarchive.git"
+    GIT_REPOSITORY ${LIBARCHIVE_GIT_REPO}
     GIT_TAG "v3.6.1"
     CMAKE_ARGS ${_LIBARCHIVE_CMAKE_ARGS}
                -DCMAKE_INSTALL_PREFIX=${PROJECT_BINARY_DIR}/libarchive

CMakeLists.txt.fmtlib

@@ -7,7 +7,7 @@ include(ExternalProject)
 ExternalProject_Add(
   fmtlib
   PREFIX ${CMAKE_CURRENT_BINARY_DIR}/fmtlib
-  GIT_REPOSITORY https://github.com/fmtlib/fmt.git
+  GIT_REPOSITORY ${LIBFMT_GIT_REPO}
   GIT_TAG 80f8d34427d40ec5e7ce3b10ededc46bd4bd5759
   CMAKE_ARGS -DCMAKE_CXX_COMPILER_LAUNCHER=${CMAKE_CXX_COMPILER_LAUNCHER}
              -DCMAKE_INSTALL_PREFIX:PATH=${CMAKE_CURRENT_BINARY_DIR}/fmtlib-install

CMakeLists.txt.gtest

@@ -4,7 +4,7 @@ project(googletest-download NONE)
 
 include(ExternalProject)
 ExternalProject_Add(googletest
-  GIT_REPOSITORY    https://github.com/google/googletest.git
+  GIT_REPOSITORY    ${GOOGLETEST_GIT_REPO}
   GIT_TAG           main
   SOURCE_DIR        "${CMAKE_CURRENT_BINARY_DIR}/googletest-src"
   BINARY_DIR        "${CMAKE_CURRENT_BINARY_DIR}/googletest-build"