devmem2: use different filename to avoid checksum conflicts

The newly resurrected devmem2.c file besides having a new location, also
updates its header, producing different checksums, which would conflict
with any previously cached or mirrored instances. To avoid such conflicts,
use a different filename in fetch(). Rename it back to original name at
unpack() for devmem2-fixups-2.patch to succeed w/o modifications.

WARNING: devmem2-1.0-r7 do_fetch: Fetcher failure for URL: 'http://www.free-electrons.com/pub/mirror/devmem2.c

'. Checksum mismatch!
File: '/OE/master/downloads/devmem2.c' has md5 checksum be12c0132a1ae118cbf5e79d98427c1d when e23f236e94be4c429aa1ceac0f01544b was expected
File: '/OE/master/downloads/devmem2.c' has sha256 checksum ec382c90af3ef2f49695ff14a4d6521e58ac482c4e29d6c9ebca8768f699c191 when 3b15515693bae1ebd14d914e46d388edfec2175829ea1576a7a0c8606ebbe639 was expected
If this change is expected (e.g. you have upgraded to a new version without updating the checksums) then you can use these lines within the recipe:
SRC_URI[md5sum] = "be12c0132a1ae118cbf5e79d98427c1d"
SRC_URI[sha256sum] = "ec382c90af3ef2f49695ff14a4d6521e58ac482c4e29d6c9ebca8768f699c191"
Otherwise you should retry the download and/or check with upstream to determine if the file has become corrupted or otherwise unexpectedly modified.

WARNING: devmem2-1.0-r7 do_fetch: Renaming /OE/sources/devmem2.c to /OE/sources/devmem2.c_bad-checksum_be12c0132a1ae118cbf5e79d98427c1d
Signed-off-by: Denys Dmytriyenko <denys@ti.com>
Signed-off-by: Armin Kuster <akuster808@gmail.com>

meta-oe/recipes-support/devmem2/devmem2.bb

@@ -3,12 +3,16 @@ LICENSE = "GPLv2+"
 LIC_FILES_CHKSUM = "file://devmem2.c;endline=38;md5=a9eb9f3890384519f435aedf986297cf"
 PR = "r7"
 
-SRC_URI = "http://www.free-electrons.com/pub/mirror/devmem2.c \
+SRC_URI = "http://www.free-electrons.com/pub/mirror/devmem2.c;downloadfilename=devmem2-new.c \
            file://devmem2-fixups-2.patch;apply=yes;striplevel=0"
 S = "${WORKDIR}"
 
 CFLAGS += "-DFORCE_STRICT_ALIGNMENT"
 
+python do_unpack_append() {
+    os.rename("devmem2-new.c", "devmem2.c")
+}
+
 do_compile() {
     ${CC} -o devmem2 devmem2.c ${CFLAGS} ${LDFLAGS}
 }