[cmake, deps] conjure common/httplib.h and remove global def for httplib macros (#3800)

httplib stuff done by @crueter on #3797

+ some extra stuff since the warning push/pop should be in header i fear :)

Signed-off-by: lizzie <lizzie@eden-emu.dev>

Co-authored-by: crueter <crueter@eden-emu.dev>
Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/3800
Reviewed-by: crueter <crueter@eden-emu.dev>
Co-authored-by: lizzie <lizzie@eden-emu.dev>
Co-committed-by: lizzie <lizzie@eden-emu.dev>

src/qt_common/CMakeLists.txt

@@ -50,7 +50,6 @@ if (USE_DISCORD_PRESENCE)
 
     if (YUZU_USE_BUNDLED_OPENSSL)
         target_link_libraries(qt_common PUBLIC OpenSSL::SSL OpenSSL::Crypto)
-        target_compile_definitions(qt_common PRIVATE CPPHTTPLIB_OPENSSL_SUPPORT)
     endif()
 
     target_compile_definitions(qt_common PUBLIC USE_DISCORD_PRESENCE)

src/qt_common/discord/discord_impl.cpp

@@ -9,7 +9,7 @@
 
 #include <QEventLoop>
 #include <boost/algorithm/string/replace.hpp>
-#include <httplib.h>
+#include "common/httplib.h"
 
 #include <discord_rpc.h>
 #include <fmt/format.h>