--- libgltf-0.1.0/configure.ac	2016-12-06 19:14:15.000000000 +0000
+++ configure.ac	2018-11-18 01:06:28.591346628 +0000
@@ -65,6 +65,8 @@
 AC_LANG_PUSH([C++])
 save_CPPFLAGS=$CPPFLAGS
 CPPFLAGS="$CPPFLAGS $GLM_CFLAGS"
+CXXFLAGS="$CXXFLAGS -DGLM_ENABLE_EXPERIMENTAL"
+AC_DEFINE([GLM_ENABLE_EXPERIMENTAL], [1], [needed for glm headers])
 AC_CHECK_HEADERS(
  glm/glm.hpp \
  glm/gtc/matrix_inverse.hpp \