userdiff: update C/C++ patterns

This pulls upstream changes from:

  git/git@8a2e8da367f7175465118510b474ad365161d6b1

  git/git@abf8f9860248d8c213600974742f18dadaa8fbb5

  git/git@407e07f2a6f55e605fda9e90cb622887269f68b5

all by Johannes Sixt <j6t@kdbg.org>.

src/userdiff.h

@@ -159,15 +159,13 @@ PATTERNS("tex", "^(\\\\((sub)*section|chapter|part)\\*{0,1}\\{.*)$",
 
 PATTERNS("cpp",
 	 /* Jump targets or access declarations */
-	 "!^[ \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 */
-	 "^((struct|class|enum)[^;]*)$",
+	 "!^[ \t]*[A-Za-z_][A-Za-z_0-9]*:[[:space:]]*($|/[/*])\n"
+	 /* functions/methods, variables, and compounds at top level */
+	 "^((::[[:space:]]*)?[A-Za-z_].*)$",
 	 /* -- */
 	 "[a-zA-Z_][a-zA-Z0-9_]*"
-	 "|[-+0-9.e]+[fFlL]?|0[xXbB]?[0-9a-fA-F]+[lL]?"
-	 "|[-+*/<>%&^|=!]=|--|\\+\\+|<<=?|>>=?|&&|\\|\\||::|->"),
+	 "|[-+0-9.e]+[fFlL]?|0[xXbB]?[0-9a-fA-F]+[lLuU]*"
+	 "|[-+*/<>%&^|=!]=|--|\\+\\+|<<=?|>>=?|&&|\\|\\||::|->\\*?|\\.\\*"),
 
 PATTERNS("csharp",
 	 /* Keywords */