diff --git a/src/libnnp/makefile b/src/libnnp/makefile
index ff20f5377..fea67d54e 100644
--- a/src/libnnp/makefile
+++ b/src/libnnp/makefile
@@ -72,11 +72,11 @@ headers: version
 
 version:
 	@$(eval GIT_VERSION = $(shell git describe --tags --always))
-	@sed -i.bak -E "s+(N2P2_GIT_VERSION) .*+\1 \"$(GIT_VERSION)\"+" version.h
+	@sed -i.bak -E "s?(N2P2_GIT_VERSION) .*?\1 \"$(GIT_VERSION)\"?" version.h
 	@$(eval GIT_REV = $(shell git rev-parse HEAD))
-	@sed -i.bak -E "s+(N2P2_GIT_REV) .*+\1 \"$(GIT_REV)\"+" version.h
+	@sed -i.bak -E "s?(N2P2_GIT_REV) .*?\1 \"$(GIT_REV)\"?" version.h
 	@$(eval GIT_BRANCH = $(shell git rev-parse --abbrev-ref HEAD))
-	@sed -i.bak -E "s+(N2P2_GIT_BRANCH) .*+\1 \"$(GIT_BRANCH)\"+" version.h
+	@sed -i.bak -E "s?(N2P2_GIT_BRANCH) .*?\1 \"$(GIT_BRANCH)\"?" version.h
 	@rm version.h.bak
 
 $(LIB).so: CFLAGS+= -fPIC
@@ -97,9 +97,9 @@ clean: clean-version clean-headers
 	$(RM) $(PROJECT_LIB)/$(LIB).so $(PROJECT_LIB)/$(LIB).a
 
 clean-version:
-	@sed -i.bak -E "s+(N2P2_GIT_VERSION) .*+\1 \"\"+" version.h
-	@sed -i.bak -E "s+(N2P2_GIT_REV) .*+\1 \"\"+" version.h
-	@sed -i.bak -E "s+(N2P2_GIT_BRANCH) .*+\1 \"\"+" version.h
+	@sed -i.bak -E "s?(N2P2_GIT_VERSION) .*?\1 \"\"?" version.h
+	@sed -i.bak -E "s?(N2P2_GIT_REV) .*?\1 \"\"?" version.h
+	@sed -i.bak -E "s?(N2P2_GIT_BRANCH) .*?\1 \"\"?" version.h
 	@rm version.h.bak
 
 clean-headers:
diff --git a/src/libnnpif/LAMMPS/Makefile.lammps b/src/libnnpif/LAMMPS/Makefile.lammps
index c9a75d141..fc83b61f8 100644
--- a/src/libnnpif/LAMMPS/Makefile.lammps
+++ b/src/libnnpif/LAMMPS/Makefile.lammps
@@ -2,4 +2,4 @@
 
 hdnnp_SYSINC =
 hdnnp_SYSLIB = -lnnpif -lnnp
-hdnnp_SYSPATH =
\ No newline at end of file
+hdnnp_SYSPATH =