[PATCH 3/3] grep: get rid of useless x < 0 comparison on an enum member

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

Remove an "p->field < 0" comparison in grep.c that'll always be
false. In this case "p" is a "grep_pat" where "field" is defined as:

	enum grep_header_field field;

And grep_header_field is in turn defined as:

    enum grep_header_field {
    	GREP_HEADER_AUTHOR = 0,
    	GREP_HEADER_COMMITTER
    };

Meaning that this comparison will always be false. This was spotted by
clang 2.9 which produced the following warning while compiling grep.c:

    grep.c:330:16: warning: comparison of unsigned enum expression < 0 is always false [-Wtautological-compare]
                    if (p->field < 0 || GREP_HEADER_FIELD_MAX <= p->field)
                        ~~~~~~~~ ^ ~

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 grep.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/grep.c b/grep.c
index b29d09c..025d3f8 100644
--- a/grep.c
+++ b/grep.c
@@ -327,7 +327,7 @@ static struct grep_expr *prep_header_patterns(struct grep_opt *opt)
 	for (p = opt->header_list; p; p = p->next) {
 		if (p->token != GREP_PATTERN_HEAD)
 			die("bug: a non-header pattern in grep header list.");
-		if (p->field < 0 || GREP_HEADER_FIELD_MAX <= p->field)
+		if (GREP_HEADER_FIELD_MAX <= p->field)
 			die("bug: unknown header field %d", p->field);
 		compile_regexp(p, opt);
 	}
-- 
1.7.6.3