C++: Fix parsing of global scope qualifiers in base class lists

See also https://sourceforge.net/p/ctags/bugs/194/

I didn't use the exact upstream patch only altering the C++ code path,
because as far as I know no c.c language recognize two consecutive
colons separated by whitespace as a single token, so there's no point
in carrying on mistakes from the past.

tagmanager/ctags/c.c

@@ -2639,7 +2639,7 @@ static boolean inheritingDeclaration (declType decl)
 
 static void processColon (statementInfo *const st)
 {
-	int c = skipToNonWhite ();
+	int c = cppGetc ();
 	const boolean doubleColon = (boolean) (c == ':');
 
 	if (doubleColon)

tests/ctags/bug1799343-1.cpp.tags

 # format=tagmanager
 C20480
-D16()0
+D16()D0
+D20480
 main16(void)0int
 x64C0int
-~D16()0
+~D16()D0

tests/ctags/bug1799343-2.cpp.tags

@@ -5,10 +5,11 @@ C
 P10
 P1A0
 Q1A0
+R1A::C0
 S1B0
-f16(int v)A::C::<anonymous>0int
+f16(int v)A::C::R0int
 t64B::S0int
 x64A::P0int
 x64P0int
 y64A::Q0int
-z64A::C::<anonymous>0int
+z64A::C::R0int