While trying a cross compile of Python 3.6 I encountered the following

alex@martha:~/src/cpython default☿ hg summary
parent: 101753:31ad7885e2e5 
 Issue #27225: Fixed a reference leak in type_new when setting __new__ fails.
branch: default
commit: (clean)
update: (current)

alex@martha:~/src/cpython default☿ ./configure --build=x86_64-linux --host=arm-linux-gnueabihf --disable-ipv6 ac_cv_file__dev_ptc=no ac_cv_file__dev_ptmx=no
checking for hg... found
...
creating Makefile
alex@martha:~/src/cpython default☿ make
...
arm-linux-gnueabihf-gcc -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes   Parser/acceler.o Parser/grammar1.o Parser/listnode.o Parser/node.o Parser/parser.o Parser/bitset.o Parser/metagrammar.o Parser/firstsets.o Parser/grammar.o Parser/pgen.o Objects/obmalloc.o Python/dynamic_annotations.o Python/mysnprintf.o Python/pyctype.o Parser/tokenizer_pgen.o Parser/printgrammar.o Parser/parsetok_pgen.o Parser/pgenmain.o -lpthread -ldl  -lpthread -lutil -o Parser/pgen
if test "yes" != "yes"; then \
	Parser/pgen ./Grammar/Grammar Include/graminit.h Python/graminit.c; \
else \
	cp ./Include/graminit.h Include/graminit.h; \
fi
cp: './Include/graminit.h' and 'Include/graminit.h' are the same file
Makefile:806: recipe for target 'Include/graminit.h' failed
make: *** [Include/graminit.h] Error 1


The attached patch allows me to get past this error. I'm unsure if it's an appropriate fix or just a workaround.