diff --git a/cmake/externals/glm/CMakeLists.txt b/cmake/externals/glm/CMakeLists.txt
index 0ca4aa3cb2..a9b4ad118d 100644
--- a/cmake/externals/glm/CMakeLists.txt
+++ b/cmake/externals/glm/CMakeLists.txt
@@ -12,4 +12,4 @@ ExternalProject_Add(
 ExternalProject_Get_Property(${EXTERNAL_NAME} INSTALL_DIR)
 
 string(TOUPPER ${EXTERNAL_NAME} EXTERNAL_NAME_UPPER)
-set(${EXTERNAL_NAME_UPPER}_INCLUDE_DIRS ${INSTALL_DIR}/include CACHE)
\ No newline at end of file
+set(${EXTERNAL_NAME_UPPER}_INCLUDE_DIRS ${INSTALL_DIR}/include CACHE TYPE "List of glm include directories")
\ No newline at end of file