[Emscripten] testcontroller error and checkkeys warning

[Sackzement]

I tried compiling SDL with Emscripten following the README-emscripten.md documentation.

Building SDL and examples work.

But building the tests fails:

[ 50%] Building C object test/CMakeFiles/checkkeys.dir/checkkeys.c.o
/path/to/SDL-git/test/checkkeys.c:237:17: warning: incompatible pointer types initializing 'const bool *' with an expression of type 'const unsigned char *' [-Wincompatible-pointer-types]
  237 |     const bool *keystate = SDL_GetKeyboardState(&max_keys);
      |                 ^          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

[ 75%] Building C object test/CMakeFiles/testcontroller.dir/testcontroller.c.o
/path/to/SDL-git/test/testcontroller.c:1175:17: error: incompatible function pointer types assigning to 'unsigned char (*)(void *, Uint16, Uint16)' (aka 'unsigned char (*)(void *, unsigned short, unsigned short)') from 'bool (void *, Uint16, Uint16)' (aka 'bool (void *, unsigned short, unsigned short)') [-Wincompatible-function-pointer-types]
 1175 |     desc.Rumble = VirtualGamepadRumble;
      |                 ^ ~~~~~~~~~~~~~~~~~~~~
/path/to/SDL-git/test/testcontroller.c:1176:25: error: incompatible function pointer types assigning to 'unsigned char (*)(void *, Uint16, Uint16)' (aka 'unsigned char (*)(void *, unsigned short, unsigned short)') from 'bool (void *, Uint16, Uint16)' (aka 'bool (void *, unsigned short, unsigned short)') [-Wincompatible-function-pointer-types]
 1176 |     desc.RumbleTriggers = VirtualGamepadRumbleTriggers;
      |                         ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/path/to/SDL-git/test/testcontroller.c:1177:17: error: incompatible function pointer types assigning to 'unsigned char (*)(void *, Uint8, Uint8, Uint8)' (aka 'unsigned char (*)(void *, unsigned char, unsigned char, unsigned char)') from 'bool (void *, Uint8, Uint8, Uint8)' (aka 'bool (void *, unsigned char, unsigned char, unsigned char)') [-Wincompatible-function-pointer-types]
 1177 |     desc.SetLED = VirtualGamepadSetLED;
      |                 ^ ~~~~~~~~~~~~~~~~~~~~

Because of the bool/unsigned char mismatch, my guess is that SDL was built with C, but the tests are built with C++.

[Sackzement]

Explicitly casting bool to unsigned char and unsigned char to bool gets rid of the errors and warning.
But I don't think it's a good fix, since compilers could build SDL with a bool extension and the problem would appear again.

diff --git a/test/checkkeys.c b/test/checkkeys.c
index c81f9aa83..98f19e90b 100644
--- a/test/checkkeys.c
+++ b/test/checkkeys.c
@@ -234,7 +234,7 @@ static void PrintText(const char *eventtype, const char *text)
 static void CountKeysDown(void)
 {
     int i, count = 0, max_keys = 0;
-    const bool *keystate = SDL_GetKeyboardState(&max_keys);
+    const bool *keystate = (const bool *)SDL_GetKeyboardState(&max_keys);
 
     for (i = 0; i < max_keys; ++i) {
         if (keystate[i]) {
diff --git a/test/testcontroller.c b/test/testcontroller.c
index 6b5874156..48ad292f1 100644
--- a/test/testcontroller.c
+++ b/test/testcontroller.c
@@ -1172,9 +1172,9 @@ static void OpenVirtualGamepad(void)
     desc.nsensors = 1;
     desc.sensors = &virtual_sensor;
     desc.SetPlayerIndex = VirtualGamepadSetPlayerIndex;
-    desc.Rumble = VirtualGamepadRumble;
-    desc.RumbleTriggers = VirtualGamepadRumbleTriggers;
-    desc.SetLED = VirtualGamepadSetLED;
+    desc.Rumble = (unsigned char (*)(void *, Uint16, Uint16))VirtualGamepadRumble;
+    desc.RumbleTriggers = (unsigned char (*)(void *, Uint16, Uint16))VirtualGamepadRumbleTriggers;
+    desc.SetLED = (unsigned char (*)(void *, Uint8, Uint8, Uint8))VirtualGamepadSetLED;
 
     virtual_id = SDL_AttachVirtualJoystick(&desc);
     if (virtual_id == 0) {

[Sackzement]

Because of the bool/unsigned char mismatch, my guess is that SDL was built with C, but the tests are built with C++.

It isn't a C/C++ mismatch, but rather a mismatch with the C standards, which are used to build SDL and the tests.

gcc/clang SDL:
__STDC__         = 1
__STDC_VERSION__ = 201710L
__cplusplus      = not defined
(bool)0.5f       = 1
-> -std=gnu17 (default) ?

gcc/clang Tests:
__STDC__         = 1
__STDC_VERSION__ = not defined
__cplusplus      = not defined
(bool)0.5f       = 0
-> -std=c89 ?

emcc SDL:
__STDC__         = 1
__STDC_VERSION__ = 201710L
__cplusplus      = not defined
(bool)0.5f       = 1
-> -std=gnu17 (default) ?

emcc Tests:
__STDC__         = 1
__STDC_VERSION__ = not defined
__cplusplus      = not defined
(bool)0.5f       = 1
-> -std=gnu89 ?