[misc] improve readability of error code handling

* Also don't pass a read size value in WriteFileWithRetry() if we don't use it.

.gitignore

@@ -1,27 +1,40 @@
 *.a
 *.aps
 *.appx
+*.appxupload
+*.bak
 *.db
 *.db-shm
 *.db-wal
 *.dep
+*.diff
+*.dll
+*.efi
 *.exe
 *.htm
 *.idb
 *.ipch
 *.la
+*.lib
 *.lo
+*.lock
 *.log
 *.mac
 *.mo
+*.mp4
 *.ncb
+*.nope
 *.o
 *.obj
+*.old
 *.opendb
 *.opt
+*.org
+*.p7x
 *.patch
 *.pc
 *.pdb
+*.pdf
 *.plg
 *.res
 *.sig