Revert "Cargo-culting for glorious victory for autocrap hegemony"

This reverts commit e706b22a. The real
problem was solved in d906981a. The
extension adds noise considering the make rules below don't comply with
the target name.

include/Makefile.am

@@ -140,7 +140,7 @@ vrt_test_SOURCES = vrt.c
 vrt.c: vrt.h
 	cp vrt.h vrt.c
 
-vrt_test$(EXEEXT): vrt.c
+vrt_test: vrt.c
 	echo "exec ${CC} -c -o _vrt_test $(top_srcdir)/include/vrt.c" > vrt_test
 	chmod +x vrt_test