diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4bb6df5..dd3550b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -80,10 +80,15 @@ list(APPEND gt_src_list
   sr_port_cm
   sr_port
   )
+foreach(d ${gt_src_list})
+  set(source_dir_${d} ${GTM_SOURCE_DIR}/${d})
+  file(GLOB sources_${d} RELATIVE ${source_dir_${d}}
+    ${d}/*.c ${d}/*.s ${d}/*.si)
+endforeach()
 
 set(includes)
 foreach(d ${gt_src_list})
-  list(APPEND includes ${GTM_SOURCE_DIR}/${d})
+  list(APPEND includes ${source_dir_${d}})
 endforeach()
 include_directories(${includes})
 include_directories(${GTM_BINARY_DIR})
@@ -91,7 +96,7 @@ include_directories(${GTM_BINARY_DIR})
 function(select_file src_var name)
   set(found "")
   foreach(d ${gt_src_list})
-    set(src "${GTM_SOURCE_DIR}/${d}/${name}")
+    set(src "${source_dir_${d}}/${name}")
     if(EXISTS "${src}")
       set(found "${src}")
       break()
@@ -103,11 +108,6 @@ function(select_file src_var name)
   set("${src_var}" "${found}" PARENT_SCOPE)
 endfunction()
 
-foreach(d ${gt_src_list})
-  file(GLOB sources_${d} RELATIVE ${CMAKE_CURRENT_SOURCE_DIR}/${d}
-    ${d}/*.c ${d}/*.s ${d}/*.si)
-endforeach()
-
 set(sources_used "")
 macro(set_source_list target)
   foreach(name ${ARGN})
@@ -116,7 +116,7 @@ macro(set_source_list target)
       if(";${sources_${d}};" MATCHES ";(${name}\\.(c|s|si));")
 	set(src ${d}/${CMAKE_MATCH_1})
 	set("source_used_${CMAKE_MATCH_1}" 1)
-	list(APPEND sources_used ${GTM_SOURCE_DIR}/${src})
+	list(APPEND sources_used ${source_dir_${d}}/${CMAKE_MATCH_1})
 	break()
       endif()
     endforeach()
@@ -175,7 +175,7 @@ foreach(d ${gt_src_list})
     if(NOT source_used_${s})
       list(APPEND libmumps_SOURCES ${d}/${s})
       set(source_used_${s} 1)
-      list(APPEND sources_used ${GTM_SOURCE_DIR}/${d}/${s})
+      list(APPEND sources_used ${source_dir_${d}}/${s})
     endif()
   endforeach()
 endforeach()