Mk/Scripts/smart_makepatch.sh: Force diff to produce the patch file i…

…nstead of "Binary files ... differ" message

It helps avoid generating wrong patches, e.g. patch-grpc.gemspec in r567838 [1].

from diff manpage:
    -a --text
        Treat all files as ASCII text.  Normally diff will simply print
	"Binary files ... differ" if files contain binary characters.
        Use of this option forces diff to produce a diff.

[1] https://cgit.FreeBSD.org/ports/diff/net/rubygem-grpc130/files/patch-grpc.gemspec?id=073c1c710a0c7254820adab9920c1903ace83fae

PR:		257027
Approved by:	mat (portmgr)

Mk/Scripts/smart_makepatch.sh

@@ -193,7 +193,7 @@ regenerate_patches() {
 		NEW=${ORIG%.orig}
 		cmp -s ${ORIG} ${NEW} && continue
 		OUT=${REGENNED}/$(std_patch_filename ${NEW})
-		TZ=UTC diff -udp ${ORIG} ${NEW} | sed \
+		TZ=UTC diff -audp ${ORIG} ${NEW} | sed \
 			-e '/^---/s|\.[0-9]* +0000$| UTC|' \
 			-e '/^+++/s|\([[:blank:]][-0-9:.+]*\)*$||' \
 			> ${OUT} || true