seen with the 3.3 branch and the trunk:

also, I think using python now unconditionally breaks the cross builds, so this should call PYTHON_FOR_BUILD, not python.

/bin/mkdir -p Include
hg: no-repository, python: found! cannot run ../Parser/asdl_c.py -h Include ../Parser/Python.asdl
/bin/mkdir -p Python
hg: no-repository, python: found! cannot run ../Parser/asdl_c.py -c Python ../Parser/Python.asdl
gcc -pthread -c -Wno-unused-result -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -g -fstack-protector --param=ssp-buffer-size=4 -Wformat -Wformat-security -Werror=format-security  -fprofile-generate -g -flto -fuse-linker-plugin -IObjects -IInclude -IPython -I. -IInclude -I../Include -D_FORTIFY_SOURCE=2   -DPy_BUILD_CORE -o Python/Python-ast.o Python/Python-ast.c
gcc: error: Python/Python-ast.c: No such file or directory
gcc: fatal error: no input files
compilation terminated.
make[3]: *** [Python/Python-ast.o] Error 4