Fix combined use of whitespace ignore options to diff

The code used to misbehave when options to ignore certain whitespaces
(-w -b and --ignore-at-eol) were combined.

Signed-off-by: Keith Cascio <keith@cs.ucla.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t4015-diff-whitespace.sh

@@ -99,11 +99,11 @@ EOF
 git diff -w > out
 test_expect_success 'another test, with -w' 'test_cmp expect out'
 git diff -w -b > out
-test_expect_failure 'another test, with -w -b' 'test_cmp expect out'
+test_expect_success 'another test, with -w -b' 'test_cmp expect out'
 git diff -w --ignore-space-at-eol > out
-test_expect_failure 'another test, with -w --ignore-space-at-eol' 'test_cmp expect out'
+test_expect_success 'another test, with -w --ignore-space-at-eol' 'test_cmp expect out'
 git diff -w -b --ignore-space-at-eol > out
-test_expect_failure 'another test, with -w -b --ignore-space-at-eol' 'test_cmp expect out'
+test_expect_success 'another test, with -w -b --ignore-space-at-eol' 'test_cmp expect out'
 
 tr 'Q' '\015' << EOF > expect
 diff --git a/x b/x
@@ -123,7 +123,7 @@ EOF
 git diff -b > out
 test_expect_success 'another test, with -b' 'test_cmp expect out'
 git diff -b --ignore-space-at-eol > out
-test_expect_failure 'another test, with -b --ignore-space-at-eol' 'test_cmp expect out'
+test_expect_success 'another test, with -b --ignore-space-at-eol' 'test_cmp expect out'
 
 tr 'Q' '\015' << EOF > expect
 diff --git a/x b/x

xdiff/xutils.c

@@ -245,12 +245,14 @@ static unsigned long xdl_hash_record_with_whitespace(char const **data,
 			while (ptr + 1 < top && isspace(ptr[1])
 					&& ptr[1] != '\n')
 				ptr++;
-			if (flags & XDF_IGNORE_WHITESPACE_CHANGE
+			if (flags & XDF_IGNORE_WHITESPACE)
+				; /* already handled */
+			else if (flags & XDF_IGNORE_WHITESPACE_CHANGE
 					&& ptr[1] != '\n') {
 				ha += (ha << 5);
 				ha ^= (unsigned long) ' ';
 			}
-			if (flags & XDF_IGNORE_WHITESPACE_AT_EOL
+			else if (flags & XDF_IGNORE_WHITESPACE_AT_EOL
 					&& ptr[1] != '\n') {
 				while (ptr2 != ptr + 1) {
 					ha += (ha << 5);