Add support for symbol table in .com files

This change fixes minor bugs and adds a feature, which lets us store the
ELF symbol table, inside the ZIP directory. We use the path /zip/.symtab
which can be safely removed using a zip editing tool, to make the binary
smaller after compilation. This supplements the existing method of using
a separate .com.dbg file, which is still supported. The intent is people
don't always know that it's a good idea to download the debug file. It's
not great having someone's first experience be a crash report, that only
has numbers rather than symbols. This will help fix that!

third_party/sqlite3/sqlite3.mk

@@ -76,6 +76,16 @@ o/$(MODE)/third_party/sqlite3/sqlite3.com.dbg:				\
 		$(APE_NO_MODIFY_SELF)
 	-@$(APELINK)
 
+o/$(MODE)/third_party/sqlite3/sqlite3.com:					\
+		o/$(MODE)/third_party/sqlite3/sqlite3.com.dbg			\
+		o/$(MODE)/third_party/infozip/zip.com				\
+		o/$(MODE)/tool/build/symtab.com
+	@$(COMPILE) -AOBJCOPY -T$@ $(OBJCOPY) -S -O binary $< $@
+	@$(COMPILE) -ASYMTAB o/$(MODE)/tool/build/symtab.com			\
+		-o o/$(MODE)/third_party/sqlite3/.sqlite3/.symtab $<
+	@$(COMPILE) -AZIP -T$@ o/$(MODE)/third_party/infozip/zip.com -9qj $@	\
+		o/$(MODE)/third_party/sqlite3/.sqlite3/.symtab
+
 $(THIRD_PARTY_SQLITE3_A):						\
 		third_party/sqlite3/					\
 		$(THIRD_PARTY_SQLITE3_A).pkg				\