diff --git a/CMakeLists.txt b/CMakeLists.txt
index dab41896..37e9f532 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -33,6 +33,12 @@ if(NOT DEFINED EXTERNALS_PREFIX_PATH)
     set(EXTERNALS_PREFIX_PATH "${TOPLEVEL_PREFIX_PATH}/externals" CACHE INTERNAL "")
 endif()
 
+if("${CMAKE_INSTALL_LIBDIR}" STREQUAL "lib64")
+    set(EXTERNALS_LIBDIR "${EXTERNALS_PREFIX_PATH}/lib64")
+else()
+    set(EXTERNALS_LIBDIR "${EXTERNALS_PREFIX_PATH}/lib")
+endif()
+
 if(NOT DEFINED RESOURCES_PREFIX_PATH)
     set(RESOURCES_PREFIX_PATH "${TOPLEVEL_PREFIX_PATH}/resources" CACHE INTERNAL "")
 endif()
@@ -56,6 +62,7 @@ message(STATUS "arch flags: " ${ENV_ARCHFLAGS})
 
 message(STATUS "      top path: " ${TOPLEVEL_PREFIX_PATH})
 message(STATUS "      lib path: " ${EXTERNALS_PREFIX_PATH})
+message(STATUS "  ext lib path: " ${EXTERNALS_LIBDIR})
 message(STATUS "  install path: " ${CMAKE_INSTALL_PREFIX})
 message(STATUS "    cmake path: " ${CMAKE_MODULE_PATH})
 message(STATUS "  cmake system: " ${CMAKE_SYSTEM_PROCESSOR})
@@ -81,7 +88,7 @@ message(STATUS "cxx-standard: " ${CMAKE_CXX_STANDARD})
 
 if(NOT EXISTS ${EXTERNALS_PREFIX_PATH})
   execute_process(COMMAND mkdir ${EXTERNALS_PREFIX_PATH})
-  execute_process(COMMAND mkdir ${EXTERNALS_PREFIX_PATH}/lib)
+  execute_process(COMMAND mkdir ${EXTERNALS_LIBDIR})  # /lib or /lib64
   execute_process(COMMAND mkdir ${EXTERNALS_PREFIX_PATH}/bin)
   execute_process(COMMAND mkdir ${EXTERNALS_PREFIX_PATH}/include)
   execute_process(COMMAND mkdir ${EXTERNALS_PREFIX_PATH}/resources)
diff --git a/cmake/extlib_jpeg.cmake b/cmake/extlib_jpeg.cmake
index 3b54d23e..19ae99ae 100644
--- a/cmake/extlib_jpeg.cmake
+++ b/cmake/extlib_jpeg.cmake
@@ -28,5 +28,5 @@ ExternalProject_Add(extlib_jpeg
     LOG_BUILD ON)
 
 add_library(jpeg STATIC IMPORTED)
-set_target_properties(jpeg PROPERTIES IMPORTED_LOCATION ${EXTERNALS_PREFIX_PATH}/lib/libjpeg.a)
+set_target_properties(jpeg PROPERTIES IMPORTED_LOCATION ${EXTERNALS_LIBDIR}/libjpeg.a)
 add_dependencies(jpeg extlib_jpeg)
diff --git a/cmake/extlib_qpdf.cmake b/cmake/extlib_qpdf.cmake
index f912ddb3..92539f62 100644
--- a/cmake/extlib_qpdf.cmake
+++ b/cmake/extlib_qpdf.cmake
@@ -32,7 +32,7 @@ ExternalProject_Add(extlib_qpdf
       --enable-crypto-native=yes\\
       --prefix=${EXTERNALS_PREFIX_PATH} \\
       CPPFLAGS=-I${EXTERNALS_PREFIX_PATH}/include \\
-      LDFLAGS="-L${EXTERNALS_PREFIX_PATH}/lib/ -L${EXTERNALS_PREFIX_PATH}/lib64/" 
+      LDFLAGS=-L${EXTERNALS_LIBDIR} 
 
     #CMAKE_ARGS \\
     #  -DCMAKE_INSTALL_PREFIX=${EXTERNALS_PREFIX_PATH} 
@@ -44,5 +44,5 @@ ExternalProject_Add(extlib_qpdf
     LOG_BUILD ON)
 
 add_library(qpdf STATIC IMPORTED)
-set_target_properties(qpdf PROPERTIES IMPORTED_LOCATION ${EXTERNALS_PREFIX_PATH}/lib/libqpdf.a)
+set_target_properties(qpdf PROPERTIES IMPORTED_LOCATION ${EXTERNALS_LIBDIR}/libqpdf.a)
 add_dependencies(qpdf extlib_qpdf)