Always automatically define WX_PRECOMP for MSVC when not disabled

Configure builds were excluded, but this would also exclude CMake
because it uses the same __WX_SETUP_H__ define.

This was done back in 248eaddf7a when there were more Windows compilers,
of which some probably used configure. But over time he check has been
reduced to only __VISUALC__ which isn't used with configure. So there is
no reason to keep this check.

See #24353, #24632.

(cherry picked from commit 4d6bcd833f)

docs/changes.txt

@@ -270,6 +270,7 @@ wxGTK:
 wxMSW:
 
 - More Windows Server versions in wxGetOsDescription() (PB, #24598, #24603).
+- Fix using wx/wxprec.h with vcpkg (Maarten Bent, #24353, #24632).
 
 wxOSX:
 

include/wx/wxprec.h

@@ -11,14 +11,10 @@
 // compiler detection; includes setup.h
 #include "wx/defs.h"
 
-// check if to use precompiled headers: do it for most Windows compilers unless
-// explicitly disabled by defining NOPCH
-#if defined(__VISUALC__)
-    // If user did not request NOCPH and we're not building using configure
-    // then assume user wants precompiled headers.
-    #if !defined(NOPCH) && !defined(__WX_SETUP_H__)
-        #define WX_PRECOMP
-    #endif
+// check if to use precompiled headers: do it for MSVC unless explicitly
+// disabled by defining NOPCH
+#if !defined(WX_PRECOMP) && defined(__VISUALC__) && !defined(NOPCH)
+    #define WX_PRECOMP
 #endif
 
 #ifdef WX_PRECOMP