Add cstdlib include to raylib.cppm

[vectorhacker]

Fixes compilation error where cstdlib is not included when building modules.

Raylib is trying to call some parts of the c standard library that are not available when using modules unless you include #include <cstdlib>, for example: free.

Example error this causes and what this change fixes

FAILED: [code=1] _deps/raylib_cpp-build/modules/CMakeFiles/raylib_cpp_modules.dir/raylib.cppm.o _deps/raylib_cpp-build/modules/CMakeFiles/raylib_cpp_modules.dir/raylib.pcm
/opt/homebrew/opt/llvm/bin/clang++ -DGRAPHICS_API_OPENGL_33 -DPLATFORM_DESKTOP -I/Users/victormartinez/dev/workspace/my_project/build/_deps/raylib_cpp-src/include -I/Users/victormartinez/dev/workspace/my_project/build/_deps/raylib-src/src -g -std=gnu++23 -arch arm64 -Wno-unused-function -MD -MT _deps/raylib_cpp-build/modules/CMakeFiles/raylib_cpp_modules.dir/raylib.cppm.o -MF _deps/raylib_cpp-build/modules/CMakeFiles/raylib_cpp_modules.dir/raylib.cppm.o.d @_deps/raylib_cpp-build/modules/CMakeFiles/raylib_cpp_modules.dir/raylib.cppm.o.modmap -o _deps/raylib_cpp-build/modules/CMakeFiles/raylib_cpp_modules.dir/raylib.cppm.o -c /Users/victormartinez/dev/workspace/my_project/build/_deps/raylib_cpp-src/modules/raylib.cppm
In file included from /Users/victormartinez/dev/workspace/my_project/build/_deps/raylib_cpp-src/modules/raylib.cppm:11:
In file included from /Users/victormartinez/dev/workspace/my_project/build/_deps/raylib_cpp-src/modules/../include/raylib-cpp.hpp:56:
/Users/victormartinez/dev/workspace/my_project/build/_deps/raylib_cpp-src/modules/../include/./ModelAnimation.hpp:42:9: error: use of undeclared identifier 'free'
   42 |         RL_FREE(modelAnimations);
      |         ^~~~~~~~~~~~~~~~~~~~~~~~
/Users/victormartinez/dev/workspace/my_project/build/_deps/raylib-src/src/raylib.h:141:33: note: expanded from macro 'RL_FREE'
  141 |     #define RL_FREE(ptr)        free(ptr)
      |                                 ^~~~
1 error generated.
[35/48] Building C object _deps/raylib-build/raylib/CMakeFiles/raylib.dir/raudio.c.o
In file included from /Users/victormartinez/dev/workspace/my_project/build/_deps/raylib-src/src/raudio.c:176:
In file included from /Users/victormartinez/dev/workspace/my_project/build/_deps/raylib-src/src/external/miniaudio.h:33505:
In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/Library/Frameworks/AudioToolbox.framework/Headers/AudioToolbox.h:43:
In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/Library/Frameworks/AudioToolbox.framework/Headers/MusicPlayer.h:44:
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/Library/Frameworks/CoreMIDI.framework/Headers/MIDIServices.h:311:32: warning: redefinition of typedef 'MIDIEventList' is a C11 feature [-Wtypedef-redefinition]
  311 | typedef struct MIDIEventList                    MIDIEventList;                  // Universal MIDI Packet
      |                                                 ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/Library/Frameworks/AudioToolbox.framework/Headers/MusicDevice.h:178:30: note: previous definition is here
  178 | typedef struct MIDIEventList MIDIEventList;
      |                              ^
In file included from /Users/victormartinez/dev/workspace/my_project/build/_deps/raylib-src/src/raudio.c:176:
In file included from /Users/victormartinez/dev/workspace/my_project/build/_deps/raylib-src/src/external/miniaudio.h:33505:
In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/Library/Frameworks/AudioToolbox.framework/Headers/AudioToolbox.h:43:
In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/Library/Frameworks/AudioToolbox.framework/Headers/MusicPlayer.h:44:
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/Library/Frameworks/CoreMIDI.framework/Headers/MIDIServices.h:528:30: warning: redefinition of typedef 'MIDIEventList' is a C11 feature [-Wtypedef-redefinition]
  528 | typedef struct MIDIEventList MIDIEventList;
      |                              ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/Library/Frameworks/CoreMIDI.framework/Headers/MIDIServices.h:311:32: note: previous definition is here
  311 | typedef struct MIDIEventList                    MIDIEventList;                  // Universal MIDI Packet
      |                                                 ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/Library/Frameworks/CoreMIDI.framework/Headers/MIDIServices.h:1034:146: warning: unknown platform 'bridgeos' in availability macro [-Wavailability]
 1034 | extern const CFStringRef        kMIDIPropertyFactoryPatchNameFile               API_DEPRECATED_WITH_REPLACEMENT("kMIDIPropertyNameConfiguration", macos(10.1, 10.2)) MIDI_API_UNAVAILABLE_NON_MACOS;
      |                                                                                                                                                                      ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/Library/Frameworks/CoreMIDI.framework/Headers/MIDIServices.h:79:20: note: expanded from macro 'MIDI_API_UNAVAILABLE_NON_MACOS'
   79 |         __OS_AVAILABILITY(bridgeos, unavailable) \
      |                           ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/Library/Frameworks/CoreMIDI.framework/Headers/MIDIServices.h:1047:144: warning: unknown platform 'bridgeos' in availability macro [-Wavailability]
 1047 | extern const CFStringRef        kMIDIPropertyUserPatchNameFile                  API_DEPRECATED_WITH_REPLACEMENT("kMIDIPropertyNameConfiguration", macos(10.1, 10.2)) MIDI_API_UNAVAILABLE_NON_MACOS;
      |                                                                                                                                                                      ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/Library/Frameworks/CoreMIDI.framework/Headers/MIDIServices.h:79:20: note: expanded from macro 'MIDI_API_UNAVAILABLE_NON_MACOS'
   79 |         __OS_AVAILABILITY(bridgeos, unavailable) \
      |                           ^
In file included from /Users/victormartinez/dev/workspace/my_project/build/_deps/raylib-src/src/raudio.c:214:
/Users/victormartinez/dev/workspace/my_project/build/_deps/raylib-src/src/external/stb_vorbis.c:1404:75: warning: pointer comparison always evaluates to false [-Wtautological-compare]
 1404 |       if (f->stream_start + loc >= f->stream_end || f->stream_start + loc < f->stream_start) {
      |                                                                           ^
5 warnings generated.
[39/48] Building CXX object 'CMakeFiles/@cmake_cxx_std.dir/opt/homebrew/opt/llvm/share/libc++/v1/std.cppm.o'
/opt/homebrew/opt/llvm/share/libc++/v1/std.cppm:163:15: warning: 'std' is a reserved name for a module [-Wreserved-module-identifier]
  163 | export module std;
      |               ^
1 warning generated.
ninja: build stopped: subcommand failed.

I had fixed this locally using a cmake patch:

file(READ "${raylib_cpp_SOURCE_DIR}/modules/raylib.cppm" _raylib_cppm)
string(REPLACE
  "module;\n\n#define BUILD_RAYLIB_CPP_MODULES"
  "module;\n\n#include <cstdlib>\n\n#define BUILD_RAYLIB_CPP_MODULES"
  _raylib_cppm "${_raylib_cppm}")
file(WRITE "${raylib_cpp_SOURCE_DIR}/modules/raylib.cppm" "${_raylib_cppm}")

[RobLoach]

thanks for the fixes here

[vectorhacker]

@RobLoach any time! Glad this library exists.