update a few URLs to use https: instead of http:

cmake/Modules/Packages/GPU.cmake

@@ -126,7 +126,7 @@ if(GPU_API STREQUAL "CUDA")
 elseif(GPU_API STREQUAL "OPENCL")
   if(${CMAKE_SYSTEM_NAME} STREQUAL "Windows")
     # download and unpack support binaries for compilation of windows binaries.
-    set(LAMMPS_THIRDPARTY_URL "http://download.lammps.org/thirdparty")
+    set(LAMMPS_THIRDPARTY_URL "https://download.lammps.org/thirdparty")
     file(DOWNLOAD "${LAMMPS_THIRDPARTY_URL}/opencl-win-devel.tar.gz" "${CMAKE_CURRENT_BINARY_DIR}/opencl-win-devel.tar.gz"
             EXPECTED_MD5 2c00364888d5671195598b44c2e0d44d)
     execute_process(COMMAND ${CMAKE_COMMAND} -E tar xzf opencl-win-devel.tar.gz WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR})

cmake/Modules/Packages/USER-SMD.cmake

@@ -9,7 +9,7 @@ if(DOWNLOAD_EIGEN3)
   message(STATUS "Eigen3 download requested - we will build our own")
   include(ExternalProject)
   ExternalProject_Add(Eigen3_build
-    URL http://bitbucket.org/eigen/eigen/get/3.3.7.tar.gz
+    URL https://bitbucket.org/eigen/eigen/get/3.3.7.tar.gz
     URL_MD5 f2a417d083fe8ca4b8ed2bc613d20f07
     CONFIGURE_COMMAND "" BUILD_COMMAND "" INSTALL_COMMAND ""
   )

lib/smd/Install.py

@@ -78,7 +78,7 @@ if pathflag:
 if buildflag:
   print("Downloading Eigen ...")
   eigentar = os.path.join(homepath, tarball)
-  url = "http://bitbucket.org/eigen/eigen/get/%s.tar.gz" % version
+  url = "https://bitbucket.org/eigen/eigen/get/%s.tar.gz" % version
   geturl(url, eigentar)
 
   # verify downloaded archive integrity via md5 checksum, if known.