diff --git a/src/Makefile.am b/src/Makefile.am
index a6aea3690e3f2045a512d7b9b4ffac538c8a5479..a05d4c69a6dfabfb921df57e38e4cadda6103d5d 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -107,12 +107,14 @@ BUILT_SOURCES = timestepping.hh timestepping.cc
 # Make sure the two are not built in parallel
 $(srcdir)/timestepping.cc: $(srcdir)/timestepping.hh
 
+EMACS ?= emacs
+
 $(srcdir)/timestepping.hh: $(srcdir)/timestepping.org
-	emacs -Q --batch --eval \
+	$(EMACS) -Q --batch --eval \
 	  "(let (vc-handled-backends) \
 	      (org-babel-tangle-file \"$<\" nil 'c++))"
 
 $(srcdir)/one-body-sample.cc: $(srcdir)/one-body-sample.org
-	emacs -Q --batch --eval \
+	$(EMACS) -Q --batch --eval \
 	  "(let (vc-handled-backends) \
 	      (org-babel-tangle-file \"$<\" nil 'c++))"