diff --git a/src/Makefile b/src/Makefile
index 06fdc26f5cdfcd9fe8cb4b2a405d8040f9fb3787..e2e9963e13f48dcaa6ffac45ee632830fd185398 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -36,6 +36,7 @@ define_bc_jgr.o \
 define_bc_subduction.o \
 define_bc_parallipipede.o \
 define_bc_model1.o \
+define_isostasy_bc.o \
 define_surface.o \
 define_cloud.o \
 define_ov.o \