Write tests for new APE loader and fix bugs

- Add FreeBSD-specific mmap() flags
- Reduce size of the APE loader from 8kb to 4kb
- Work towards fixing the Makefile build on WSL
- Automate testing of APE no-modify-self behaviors
- Make the ape.S shell script code cleaner and tinier
- Improve the APE sanity check to test behavior better
- Fixed issue with ShowCrashReports() sigaltstack() on BSDs
- Delete symbols for S_MODE magnums which wasted compile time

If you checked out yesterday's APE commit, please run:

    rm -f /usr/bin/ape o/tmp/ape /tmp/ape "${TMPDIR:-/tmp}/ape"

Because this change fixes certain aspects of the new ABI. We don't have
automated migrations for APE loader versions yet. Thanks! You can also
download prebuilt binaries here:

- https://justine.lol/ape.elf    (Linux/FreeBSD/NetBSD/OpenBSD)
- https://justine.lol/ape.macho  (Apple)

Install the appropriate one as `/usr/bin/ape`.

test/libc/runtime/test.mk

@@ -41,6 +41,8 @@ TEST_LIBC_RUNTIME_DIRECTDEPS =					\
 	LIBC_TINYMATH						\
 	LIBC_UNICODE						\
 	LIBC_X							\
+	LIBC_ZIPOS						\
+	TOOL_BUILD_LIB						\
 	THIRD_PARTY_XED
 
 TEST_LIBC_RUNTIME_DEPS :=					\
@@ -59,6 +61,15 @@ o/$(MODE)/test/libc/runtime/%.com.dbg:				\
 		$(APE)
 	@$(APELINK)
 
+o/$(MODE)/test/libc/runtime/ape_test.com.dbg:			\
+		$(TEST_LIBC_RUNTIME_DEPS)			\
+		o/$(MODE)/test/libc/runtime/ape_test.o		\
+		o/$(MODE)/test/libc/runtime/runtime.pkg		\
+		$(LIBC_TESTMAIN)				\
+		$(CRT)						\
+		$(APE)
+	@$(APELINK)
+
 $(TEST_LIBC_RUNTIME_OBJS):					\
 	DEFAULT_CCFLAGS +=					\
 		-fno-builtin
@@ -67,7 +78,6 @@ o/$(MODE)/test/libc/runtime/getenv_test.com.runs:		\
 		o/$(MODE)/test/libc/runtime/getenv_test.com
 	@HELLO=THERE build/runit $@ $<
 
-o/$(MODE)/test/libc/runtime/fun_test.o				\
 o/$(MODE)/test/libc/runtime/itsatrap_test.o:			\
 		OVERRIDE_CFLAGS +=				\
 			-fno-sanitize=all			\