diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index ad0dd52..ff746c2 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -6,15 +6,15 @@ elseif(UNIX)
 endif()
 
 if(CMAKE_C_COMPILER_ID MATCHES "^(Intel)$")
-  set(CMAKE_C_FLAGS "-g")
+  set(CMAKE_C_FLAGS "-g ${CMAKE_C_FLAGS}")
   set(CMAKE_C_FLAGS_RELEASE "-O3")
-  set(CMAKE_Fortran_FLAGS "-g")
+  set(CMAKE_Fortran_FLAGS "-g ${CMAKE_Fortran_FLAGS}")
   set(CMAKE_Fortran_FLAGS_RELEASE "-O3")
 elseif(CMAKE_C_COMPILER_ID MATCHES "^(GNU|Clang|AppleClang)$")
-  set(CMAKE_C_FLAGS "-g")
+  set(CMAKE_C_FLAGS "-g ${CMAKE_C_FLAGS}")
   set(CMAKE_C_FLAGS_RELEASE "-O3")
   set(CMAKE_C_FLAGS_DEBUG "-ggdb -Wall")
-  set(CMAKE_Fortran_FLAGS "-g -fbacktrace -funroll-loops")
+  set(CMAKE_Fortran_FLAGS "-g -fbacktrace -funroll-loops ${CMAKE_Fortran_FLAGS}")
   set(CMAKE_Fortran_FLAGS_RELEASE "-O3")
   set(CMAKE_Fortran_FLAGS_DEBUG "-ggdb -Wall")
 endif()