iidx: workaround for touch monitors that report contact area (#462)

## Link to GitHub Issue, if one exists
n/a

## Description of change
When touch monitors send touch area size information
(`TOUCHEVENTFMASK_CONTACTAREA` flag and `cxContact` / `cyContact` fields
of `TOUCHINPUT` struct) from `GetTouchInputInfo`, IIDX gets confused and
does some unexpected things when interacting with the subscreen.

As a workaround, hook `GetTouchInputInfo` and clear out the flag &
values.

This is only done for IIDX AND when -iidxnativetouch is on.

## Testing
Tested on a Dell touch monitor, simulating "bad" values.

src/spice2x/misc/nativetouchhook.cpp

@@ -0,0 +1,91 @@
+// enable touch functions - set version to windows 7
+// mingw otherwise doesn't load touch stuff
+#define _WIN32_WINNT 0x0601
+
+#include "wintouchemu.h"
+
+#include "util/detour.h"
+#include "util/logging.h"
+
+#define TOUCH_SIMULATE_FAT_FINGERS 0
+#define TOUCH_DEBUG_VERBOSE 0
+
+#if TOUCH_DEBUG_VERBOSE
+#define log_debug(module, format_str, ...) logger::push( \
+    LOG_FORMAT("M", module, format_str, ## __VA_ARGS__), logger::Style::GREY)
+#else
+#define log_debug(module, format_str, ...)
+#endif
+
+namespace nativetouchhook {
+
+    static decltype(GetTouchInputInfo) *GetTouchInputInfo_orig = nullptr;
+
+    static void strip_contact_size(PTOUCHINPUT point) {
+
+#if TOUCH_SIMULATE_FAT_FINGERS
+        point->dwMask |= 0x004;
+        point->cxContact = 80 * 100;
+        point->cyContact = 60 * 100;
+#endif
+
+        // most monitors do not set TOUCHEVENTFMASK_CONTACTAREA, but for
+        // monitors that do set it, IIDX can get very confused (SDVX is not
+        // affected)
+        //
+        // while the test menu and the touch "glow" seem to work properly,
+        // interacting with subscreen menu items or entering PIN becomes
+        // very unpredictable
+        //
+        // to fix this, simply remove the contact area width and height
+        // 
+        // note: test menu > I/O > touch test  gives 5 numbers:
+        //       n: x, y, w, h
+        //       where 
+        //       n is the nth touch input since boot
+        //       x, y are coordinates (center of finger)
+        //       w, h are contact width and height
+        //
+        // when TOUCHEVENTFMASK_CONTACTAREA is not set, w/h will
+        // automatically be seen as 1x1, which works perfectly fine
+
+        log_debug(
+            "touch::native",
+            "[{}, {}] dwMask = 0x{:x}, cxContact = {}, cyContact = {}",
+            point->x / 100,
+            point->y / 100,
+            point->dwMask,
+            point->cxContact,
+            point->cyContact);
+
+        point->dwMask &= ~(0x004ul); // clear TOUCHEVENTFMASK_CONTACTAREA 
+        point->cxContact = 0;
+        point->cyContact = 0;
+    }
+
+    static BOOL WINAPI GetTouchInputInfoHook(
+        HTOUCHINPUT hTouchInput, UINT cInputs, PTOUCHINPUT pInputs, int cbSize) {
+
+        // call the original fist
+        const auto result = GetTouchInputInfo_orig(hTouchInput, cInputs, pInputs, cbSize);
+        if (result == 0) {
+            return result;
+        }
+
+        for (size_t i = 0; i < cInputs; i++) {
+            PTOUCHINPUT point = &pInputs[i];
+            strip_contact_size(point);
+        }
+        
+        return result;
+    }
+
+    void hook(HMODULE module) {
+        GetTouchInputInfo_orig = detour::iat_try("GetTouchInputInfo", GetTouchInputInfoHook, module);
+        if (GetTouchInputInfo_orig != nullptr) {
+            log_misc("touch::native", "GetTouchInputInfo hooked");
+        }
+    }
+
+}
+