Add new option DEP_DOWNLOAD_DIR and go with URLs everywhere

deps/CMakeLists.txt

@@ -32,6 +32,7 @@ if (NPROC EQUAL 0)
 endif ()
 
 set(DESTDIR "${CMAKE_CURRENT_BINARY_DIR}/destdir" CACHE PATH "Destination directory")
+set(DEP_DOWNLOAD_DIR ${CMAKE_CURRENT_BINARY_DIR} CACHE PATH "Path for downloaded source packages.")
 
 option(DEP_DEBUG "Build debug variants (only applicable on Windows)" ON)
 
@@ -46,6 +47,7 @@ endif()
 # option(DEP_BUILD_IGL_STATIC "Build IGL as a static library. Might cause link errors and increase binary size." OFF)
 
 message(STATUS "PrusaSlicer deps DESTDIR: ${DESTDIR}")
+message(STATUS "PrusaSlicer dowload dir for source packages: ${DEP_DOWNLOAD_DIR}")
 message(STATUS "PrusaSlicer deps debug build: ${DEP_DEBUG}")
 
 find_package(Git REQUIRED)
@@ -71,6 +73,7 @@ function(prusaslicer_add_cmake_project projectname)
         dep_${projectname}
         EXCLUDE_FROM_ALL    ON
         INSTALL_DIR         ${DESTDIR}/usr/local
+        DOWNLOAD_DIR        ${DEP_DOWNLOAD_DIR}/${projectname}
         ${_gen}
         CMAKE_ARGS
             -DCMAKE_INSTALL_PREFIX:STRING=${DESTDIR}/usr/local
@@ -187,23 +190,6 @@ set(_dep_list
     ${EXPAT_PKG}
     )
 
-if ("${CMAKE_SIZEOF_VOID_P}" STREQUAL "8")
-    # Patch the boost::polygon library with a custom one.
-    ExternalProject_Add(dep_boost_polygon
-        EXCLUDE_FROM_ALL ON
-        GIT_REPOSITORY "https://github.com/prusa3d/polygon"
-        GIT_TAG prusaslicer_gmp
-        DEPENDS dep_Boost
-        CONFIGURE_COMMAND ""
-        BUILD_COMMAND ""
-        INSTALL_COMMAND ${CMAKE_COMMAND} -E copy_directory
-            "${CMAKE_CURRENT_BINARY_DIR}/dep_boost_polygon-prefix/src/dep_boost_polygon/include/boost/polygon"
-            "${DESTDIR}/usr/local/include/boost/polygon"
-    )
-    # Only override boost::Polygon Voronoi implementation with Vojtech's GMP hacks on 64bit platforms.
-    list(APPEND _dep_list "dep_boost_polygon")
-endif ()
-
 if (MSVC)
     # Experimental
     #list(APPEND _dep_list "dep_qhull")