reduce misuse of error codes from errno.h

src/adb.c

src/adb_walk_genadb.c

src/apk_adb.c

src/apk_crypto.h

src/apk_defines.h

src/app_convndx.c

src/app_extract.c

src/app_fetch.c

src/app_mkndx.c

src/crypto_openssl.c

src/database.c

src/io.c

src/io_archive.c

src/io_url.c

src/package.c

src/print.c

src/trust.c