Error compiling on Linux

[FXM56K]

Hi everyone I'm having this weird issue with the code, the software complies to 71% and fails every time, seems there is some sort of error in the code, or maybe my pc? can you help please?. My current distro is ArchLinux, thanks in advance!.

[ 71%] Building CXX object CMakeFiles/OpenTomb.dir/src/state_control/state_control_LaraWeapons.cpp.o
In file included from /home/faben/OpenTomb/src/state_control/state_control_LaraWeapons.cpp:3:
/home/faben/OpenTomb/src/state_control/../core/system.h:57:22: error: ‘size_t’ was not declared in this scope
57 | void *Sys_GetTempMem(size_t size);
| ^~~~~~
/home/faben/OpenTomb/src/state_control/../core/system.h:12:1: note: ‘size_t’ is defined in header ‘’; did you forget to ‘#include ’?
11 | #include <SDL2/SDL_opengl.h>
+++ |+#include
12 |
/home/faben/OpenTomb/src/state_control/../core/system.h:58:6: error: variable or field ‘Sys_ReturnTempMem’ declared void
58 | void Sys_ReturnTempMem(size_t size);
| ^~~~~~~~~~~~~~~~~
/home/faben/OpenTomb/src/state_control/../core/system.h:58:24: error: ‘size_t’ was not declared in this scope
58 | void Sys_ReturnTempMem(size_t size);
| ^~~~~~
/home/faben/OpenTomb/src/state_control/../core/system.h:58:24: note: ‘size_t’ is defined in header ‘’; did you forget to ‘#include ’?
/home/faben/OpenTomb/src/state_control/../core/system.h:64:29: error: ‘size_t’ has not been declared
64 | void Sys_Strtime(char *buf, size_t buf_size);
| ^~~~~~
make[2]: *** [CMakeFiles/OpenTomb.dir/build.make:832: CMakeFiles/OpenTomb.dir/src/state_control/state_control_LaraWeapons.cpp.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:138: CMakeFiles/OpenTomb.dir/all] Error 2
make: *** [Makefile:91: all] Error 2

[RICCIARDI-Adrien]

Hi,
Try adding #include <unistd.h> to src/core/system.h and retry build.