Avoid the use of .PHONY (target s created twice and I have no idea if it's right).

plugins-root/Makefile.am

@@ -2,6 +2,8 @@
 
 NP-VERSION-FILE: .FORCE-NP-VERSION-FILE
 	@$(SHELL_PATH) $(top_srcdir)/NP-VERSION-GEN
+.FORCE-NP-VERSION-FILE:
+
 -include NP-VERSION-FILE
 
 AM_CFLAGS = -DNP_VERSION='"$(NP_VERSION)"'
@@ -86,4 +88,3 @@ all-local: .FORCE-NP-VERSION-FILE
 clean-local:
 	rm -f NP-VERSION-FILE
 
-.PHONY: .FORCE-NP-VERSION-FILE

plugins-scripts/Makefile.am

@@ -2,6 +2,8 @@
 
 NP-VERSION-FILE: .FORCE-NP-VERSION-FILE
 	@$(SHELL_PATH) $(top_srcdir)/NP-VERSION-GEN
+.FORCE-NP-VERSION-FILE:
+
 -include NP-VERSION-FILE
 
 export NP_VERSION:= $(NP_VERSION)
@@ -47,4 +49,3 @@ CLEANFILES=$(libexec_SCRIPTS)
 clean-local:
 	rm -f NP-VERSION-FILE
 
-.PHONY: .FORCE-NP-VERSION-FILE

plugins/Makefile.am

@@ -2,6 +2,8 @@
 
 NP-VERSION-FILE: .FORCE-NP-VERSION-FILE
 	@$(SHELL_PATH) $(top_srcdir)/NP-VERSION-GEN
+.FORCE-NP-VERSION-FILE:
+
 -include NP-VERSION-FILE
 
 AM_CFLAGS = -DNP_VERSION='"$(NP_VERSION)"'
@@ -177,5 +179,3 @@ clean-local:
 uninstall-local:
 	cd $(DESTDIR)$(libexecdir) && rm -f $(check_tcp_programs)
 
-.PHONY: .FORCE-NP-VERSION-FILE
-