diff --git a/bindings/pyroot/CMakeLists.txt b/bindings/pyroot/CMakeLists.txt
index c537bae..3a2118e 100644
--- a/bindings/pyroot/CMakeLists.txt
+++ b/bindings/pyroot/CMakeLists.txt
@@ -36,8 +36,13 @@ endif()
 file(GLOB pyfiles RELATIVE ${CMAKE_CURRENT_SOURCE_DIR} *.py)
 foreach(pyfile ${pyfiles})
   install(FILES ${pyfile} DESTINATION ${runtimedir})
-  install(CODE "execute_process(COMMAND python -m py_compile \$ENV{DESTDIR}${runtimedir}/${pyfile})")
-  install(CODE "execute_process(COMMAND python -O -m py_compile \$ENV{DESTDIR}${runtimedir}/${pyfile})")
+  if(IS_ABSOLUTE ${runtimedir})
+    set(absruntimedir ${runtimedir})
+  else()
+    set(absruntimedir ${CMAKE_INSTALL_PREFIX}/${runtimedir})
+  endif()
+  install(CODE "execute_process(COMMAND ${PYTHON_EXECUTABLE} -m py_compile \$ENV{DESTDIR}${absruntimedir}/${pyfile})")
+  install(CODE "execute_process(COMMAND ${PYTHON_EXECUTABLE} -O -m py_compile \$ENV{DESTDIR}${absruntimedir}/${pyfile})")
   file(COPY ${pyfile} DESTINATION ${localruntimedir})
 endforeach()
 
diff --git a/main/CMakeLists.txt b/main/CMakeLists.txt
index 0f430c9..a431a2b 100644
--- a/main/CMakeLists.txt
+++ b/main/CMakeLists.txt
@@ -43,7 +43,12 @@ if(python)
   endforeach()
 
   install(FILES python/cmdLineUtils.py DESTINATION ${runtimedir})
-  install(CODE "execute_process(COMMAND ${PYTHON_EXECUTABLE} -m py_compile \$ENV{DESTDIR}${runtimedir}/cmdLineUtils.py)")
-  install(CODE "execute_process(COMMAND ${PYTHON_EXECUTABLE} -O -m py_compile \$ENV{DESTDIR}${runtimedir}/cmdLineUtils.py)")
+  if(IS_ABSOLUTE ${runtimedir})
+    set(absruntimedir ${runtimedir})
+  else()
+    set(absruntimedir ${CMAKE_INSTALL_PREFIX}/${runtimedir})
+  endif()
+  install(CODE "execute_process(COMMAND ${PYTHON_EXECUTABLE} -m py_compile \$ENV{DESTDIR}${absruntimedir}/cmdLineUtils.py)")
+  install(CODE "execute_process(COMMAND ${PYTHON_EXECUTABLE} -O -m py_compile \$ENV{DESTDIR}${absruntimedir}/cmdLineUtils.py)")
   configure_file(python/cmdLineUtils.py ${localruntimedir}/cmdLineUtils.py @ONLY)
 endif()