[PATCH] Avoid false positives in label detection in cpp diff hunk header regex.

A C++ method start such as

        void
        foo::bar()

wasn't recognized by cpp diff driver as it mistakenly included "foo::bar" as a
label. However the colon in a label can't be followed by another colon, so
recognize this case specially to correctly detect C++ methods using this style.

Signed-off-by: Vadim Zeitlin <redacted>
---
 userdiff.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/userdiff.c b/userdiff.c
index ea43a03..9415586 100644
--- a/userdiff.c
+++ b/userdiff.c

@@ -125,7 +125,7 @@ PATTERNS("tex",

"^(\\\\((sub)*section|chapter|part)\\*{0,1}\\{.*)$",
         "\\\\[a-zA-Z@]+|\\\\.|[a-zA-Z0-9\x80-\xff]+"),
 PATTERNS("cpp",
         /* Jump targets or access declarations */
-        "!^[ \t]*[A-Za-z_][A-Za-z_0-9]*:.*$\n"
+        "!^[ \t]*[A-Za-z_][A-Za-z_0-9]*:([^:].*$|$)\n"
         /* C/++ functions/methods at top level */
         "^([A-Za-z_][A-Za-z_0-9]*([ \t*]+[A-Za-z_][A-Za-z_0-9]*([ \t]*::[
\t]*[^[:space:]]+)?){1,}[ \t]*\\([^;]*)$\n"
         /* compound type at top level */
--
1.8.2.135.g7b592fa