diff: migrate diff_flags.pickaxe_ignore_case to a pickaxe_opts bit

Currently flags for pickaxing are found in different places. Unify the
flags into the `pickaxe_opts` field, which will contain any pickaxe related
flags.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff.h

@@ -91,7 +91,6 @@ struct diff_flags {
 	unsigned override_submodule_config:1;
 	unsigned dirstat_by_line:1;
 	unsigned funccontext:1;
-	unsigned pickaxe_ignore_case:1;
 	unsigned default_follow_renames:1;
 };
 
@@ -327,6 +326,8 @@ extern void diff_setup_done(struct diff_options *);
 #define DIFF_PICKAXE_KIND_S	4 /* traditional plumbing counter */
 #define DIFF_PICKAXE_KIND_G	8 /* grep in the patch */
 
+#define DIFF_PICKAXE_IGNORE_CASE	32
+
 extern void diffcore_std(struct diff_options *);
 extern void diffcore_fix_diff_index(struct diff_options *);
 

diffcore-pickaxe.c

@@ -222,11 +222,11 @@ void diffcore_pickaxe(struct diff_options *o)
 
 	if (opts & (DIFF_PICKAXE_REGEX | DIFF_PICKAXE_KIND_G)) {
 		int cflags = REG_EXTENDED | REG_NEWLINE;
-		if (o->flags.pickaxe_ignore_case)
+		if (o->pickaxe_opts & DIFF_PICKAXE_IGNORE_CASE)
 			cflags |= REG_ICASE;
 		regcomp_or_die(&regex, needle, cflags);
 		regexp = &regex;
-	} else if (o->flags.pickaxe_ignore_case &&
+	} else if (o->pickaxe_opts & DIFF_PICKAXE_IGNORE_CASE &&
 		   has_non_ascii(needle)) {
 		struct strbuf sb = STRBUF_INIT;
 		int cflags = REG_NEWLINE | REG_ICASE;
@@ -236,7 +236,7 @@ void diffcore_pickaxe(struct diff_options *o)
 		strbuf_release(&sb);
 		regexp = &regex;
 	} else {
-		kws = kwsalloc(o->flags.pickaxe_ignore_case
+		kws = kwsalloc(o->pickaxe_opts & DIFF_PICKAXE_IGNORE_CASE
 			       ? tolower_trans_tbl : NULL);
 		kwsincr(kws, needle, strlen(needle));
 		kwsprep(kws);

revision.c

@@ -2076,7 +2076,7 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
 		revs->grep_filter.pattern_type_option = GREP_PATTERN_TYPE_ERE;
 	} else if (!strcmp(arg, "--regexp-ignore-case") || !strcmp(arg, "-i")) {
 		revs->grep_filter.ignore_case = 1;
-		revs->diffopt.flags.pickaxe_ignore_case = 1;
+		revs->diffopt.pickaxe_opts |= DIFF_PICKAXE_IGNORE_CASE;
 	} else if (!strcmp(arg, "--fixed-strings") || !strcmp(arg, "-F")) {
 		revs->grep_filter.pattern_type_option = GREP_PATTERN_TYPE_FIXED;
 	} else if (!strcmp(arg, "--perl-regexp") || !strcmp(arg, "-P")) {