diff --git a/.devel b/.devel
new file mode 100644
index 0000000..e69de29
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8a5712f..ba6f6c6 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -16,7 +16,7 @@ set(CMAKE_C_STANDARD_REQUIRED ON)
 # Optional configure for developer mode to generate source code from org-mode files.
 option(TREXIO_DEVEL "TREXIO developer mode (for code generation)." OFF)
 
-if(EXISTS "${CMAKE_SOURCE_DIR}/.git/config")
+if(EXISTS "${CMAKE_SOURCE_DIR}/.devel")
   set(TREXIO_DEVEL ON)
   find_package(Python3 REQUIRED)
   if(Python3_FOUND)
diff --git a/configure.ac b/configure.ac
index 3ef8c86..cd0a7b2 100644
--- a/configure.ac
+++ b/configure.ac
@@ -16,10 +16,10 @@ AM_PROG_AR
 LT_PREREQ([2.2])
 LT_INIT
 
-# Activate developer mode when the source is the git repository.
+# Activate developer mode when if a dummy file is present (true when cloning the git repository).
 # Otherwise, it is the source distribution and the developer mode should not be activated.
-TEST_IFEXISTS=".git"
-AS_IF([test -d $TEST_IFEXISTS],
+TEST_IFEXISTS=".devel"
+AS_IF([test -f $TEST_IFEXISTS],
         [enable_maintainer_mode="yes"]
 )