Fix: ensure we include the right Lua header files (#7842)

#### Brief overview of PR changes/additions
For Windows builds modify the `#include` lines for Lua header files to
specify the 5.1 version. Also accommodate some changes in our CI build
environment:
* For some reason (maybe because of a more modern linker) we need to
specify the original PCRE library with `-lpcre` rather than `-lpcre-1` -
the exact cause of this is not clear but thanks to @jmckisson for
finding it (and using it in his attempt to solve the same problems this
PR is doing).
* It seems the Window building is now being done in the `C:` drive
rather than the previous `D:` one, so a tweak to clean the colon
containing file-system root specifier to the alternative that
MSYS2+Mingw-w64 uses which instead uses a (POSIX) `/` root directory
followed by a single lower-case letter to specify the drive needs to be
extended to handle both drives. This is because the scripts use `rsync`
and that treats any `:` as the separator between host and path and gets
confused when it sees a "Windows" path containing it!

#### Motivation for adding to Mudlet
The default version - and the one needed for some packages like Luarocks
is a 5.4 one - and that includes header files in the "default" `include`
directory. So the headers that get pulled in are the wrong ones, which
fail to work as they are not compatible with Lua 5.1; to get the 5.1
instead I believe we need to explicitly include the version specific
sub-directory in the `#include` lines.

Other tweaks are also needed "to get things working nowadays."

#### Other info (issues closed, discussion etc)
This should be simpler to do than what is being attempted by #7841.

---------

Signed-off-by: Stephen Lyons <slysven@virginmedia.com>

test/TLuaInterfaceTest.cpp

@@ -23,11 +23,18 @@
 #include <QtTest/QtTest>
 
 extern "C" {
-    #include <lauxlib.h>
-    #include <lua.h>
-    #include <lualib.h>
+#if defined(INCLUDE_VERSIONED_LUA_HEADERS)
+#include <lua5.1/lauxlib.h>
+#include <lua5.1/lua.h>
+#include <lua5.1/lualib.h>
+#else
+#include <lauxlib.h>
+#include <lua.h>
+#include <lualib.h>
+#endif
 }
 
+
 class TVarTest : public QObject {
 Q_OBJECT