coccinelle: put sane filenames into output patches

Coccinelle outputs its suggested transformations as patches, whose header looks something like this: --- commit.c +++ /tmp/cocci-output-19250-7ae78a-commit.c Note the lack of 'diff --opts <old> <new>' line, the differing number of path components on the --- and +++ lines, and the nonsensical filename on the +++ line. 'patch -p0' can still apply these patches, as it takes the filename to be modified from the --- line. Alas, 'git apply' can't, because it takes the filename from the +++ line, and then complains about the nonexisting file. Pass the '--patch .' options to Coccinelle via the SPATCH_FLAGS 'make' variable, as it seems to make it generate proper context diff patches, with the header starting with a 'diff ...' line and containing sane filenames. The resulting 'contrib/coccinelle/*.cocci.patch' files then can be applied both with 'git apply' and 'patch' (even without '-p0'). Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>