Rename python -> python3 (closes #1144) (#1187)

When we removed the com suffix from ape binaries, we broke the build for
ape's python for any case-insensitive file system, i.e. Windows and XNU,
because there is a third_party/python/Python that gets mirrored in the o
directory with the python object files and clashes with the binary name.
This patch hacks around this by renaming the binary to "python3" so that
it no longer clashes with that directory.

Author: mrdomino

third_party/python/BUILD.mk

@@ -7,7 +7,7 @@ THIRD_PARTY_PYTHON_ARTIFACTS =						\
 	THIRD_PARTY_PYTHON_STAGE1_A					\
 	THIRD_PARTY_PYTHON_STAGE2_A					\
 	THIRD_PARTY_PYTHON_PYTEST_A					\
-	THIRD_PARTY_PYTHON_PYTHON					\
+	THIRD_PARTY_PYTHON_PYTHON3					\
 	THIRD_PARTY_PYTHON_FREEZE
 
 THIRD_PARTY_PYTHON_BINS =						\
@@ -17,7 +17,7 @@ THIRD_PARTY_PYTHON_BINS =						\
 THIRD_PARTY_PYTHON_COMS =						\
 	o/$(MODE)/third_party/python/Parser/asdl_c			\
 	o/$(MODE)/third_party/python/pystone				\
-	o/$(MODE)/third_party/python/python				\
+	o/$(MODE)/third_party/python/python3				\
 	o/$(MODE)/third_party/python/freeze				\
 	o/$(MODE)/third_party/python/pycomp				\
 	o/$(MODE)/third_party/python/pyobj				\
@@ -29,7 +29,7 @@ THIRD_PARTY_PYTHON_CHECKS =						\
 	$(THIRD_PARTY_PYTHON_STAGE2_A).pkg				\
 	$(THIRD_PARTY_PYTHON_PYTEST_A).pkg				\
 	$(THIRD_PARTY_PYTHON_HDRS:%=o/$(MODE)/%.ok)			\
-	o/$(MODE)/third_party/python/python.pkg				\
+	o/$(MODE)/third_party/python/python3.pkg			\
 	o/$(MODE)/third_party/python/freeze.pkg
 
 # TODO: Deal with aarch64 under qemu not making execve() easy.
@@ -3980,12 +3980,12 @@ THIRD_PARTY_PYTHON_SRCS =						\
 ################################################################################
 # PYTHON
 
-THIRD_PARTY_PYTHON_PYTHON_SRCS = third_party/python/python.c
-THIRD_PARTY_PYTHON_PYTHON_OBJS = o/$(MODE)/third_party/python/python.o
-THIRD_PARTY_PYTHON_PYTHON_COMS = o/$(MODE)/third_party/python/python
-THIRD_PARTY_PYTHON_PYTHON_BINS = $(THIRD_PARTY_PYTHON_PYTHON_COMS) $(THIRD_PARTY_PYTHON_PYTHON_COMS:%=%.dbg)
-THIRD_PARTY_PYTHON_PYTHON_DEPS = $(call uniq,$(foreach x,$(THIRD_PARTY_PYTHON_PYTHON_DIRECTDEPS),$($(x))))
-THIRD_PARTY_PYTHON_PYTHON_DIRECTDEPS =					\
+THIRD_PARTY_PYTHON_PYTHON3_SRCS = third_party/python/python3.c
+THIRD_PARTY_PYTHON_PYTHON3_OBJS = o/$(MODE)/third_party/python/python3.o
+THIRD_PARTY_PYTHON_PYTHON3_COMS = o/$(MODE)/third_party/python/python3
+THIRD_PARTY_PYTHON_PYTHON3_BINS = $(THIRD_PARTY_PYTHON_PYTHON3_COMS) $(THIRD_PARTY_PYTHON_PYTHON3_COMS:%=%.dbg)
+THIRD_PARTY_PYTHON_PYTHON3_DEPS = $(call uniq,$(foreach x,$(THIRD_PARTY_PYTHON_PYTHON3_DIRECTDEPS),$($(x))))
+THIRD_PARTY_PYTHON_PYTHON3_DIRECTDEPS =					\
 	LIBC_CALLS							\
 	LIBC_FMT							\
 	LIBC_INTRIN							\
@@ -4005,14 +4005,14 @@ THIRD_PARTY_PYTHON_PYTHON_DIRECTDEPS =					\
 	THIRD_PARTY_XED							\
 	TOOL_ARGS
 
-o/$(MODE)/third_party/python/python.pkg:				\
-		$(THIRD_PARTY_PYTHON_PYTHON_OBJS)			\
-		$(foreach x,$(THIRD_PARTY_PYTHON_PYTHON_DIRECTDEPS),$($(x)_A).pkg)
+o/$(MODE)/third_party/python/python3.pkg:				\
+		$(THIRD_PARTY_PYTHON_PYTHON3_OBJS)			\
+		$(foreach x,$(THIRD_PARTY_PYTHON_PYTHON3_DIRECTDEPS),$($(x)_A).pkg)
 
-o/$(MODE)/third_party/python/python.dbg:				\
-		o/$(MODE)/third_party/python/python.pkg			\
-		$(THIRD_PARTY_PYTHON_PYTHON_DEPS)			\
-		$(THIRD_PARTY_PYTHON_PYTHON_OBJS)			\
+o/$(MODE)/third_party/python/python3.dbg:				\
+		o/$(MODE)/third_party/python/python3.pkg		\
+		$(THIRD_PARTY_PYTHON_PYTHON3_DEPS)			\
+		$(THIRD_PARTY_PYTHON_PYTHON3_OBJS)			\
 		$(CRT)							\
 		$(APE_NO_MODIFY_SELF)
 	@$(APELINK)