error: ‘size_t’ has not been declared while building

When I run the cmake --build . command I get the following:

$> cmake --build .
[  5%] Building CXX object source/lib/CMakeFiles/vcaLib.dir/vcaLib.cpp.o
In file included from /home/user/VCA/source/lib/vcaLib.cpp:21:
/home/user/VCA/source/lib/vcaLib.h:197:42: error: ‘size_t’ has not been declared
  197 |                                          size_t num_frames);
      |                                          ^~~~~~
make[2]: *** [source/lib/CMakeFiles/vcaLib.dir/build.make:76: source/lib/CMakeFiles/vcaLib.dir/vcaLib.cpp.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:116: source/lib/CMakeFiles/vcaLib.dir/all] Error 2
make: *** [Makefile:136: all] Error 2

Here is the output of the cmake ../ command:

-- The C compiler identification is GNU 11.2.0
-- The CXX compiler identification is GNU 11.2.0
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /usr/bin/cc - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/c++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- VCA version v1.0.0+4-gae74a03
-- Looking for pthread.h
-- Looking for pthread.h - found
-- Performing Test CMAKE_HAVE_LIBC_PTHREAD
-- Performing Test CMAKE_HAVE_LIBC_PTHREAD - Success
-- Found Threads: TRUE
-- Detected x86_64 target processor
-- The ASM_NASM compiler identification is NASM
-- Found assembler: /usr/bin/nasm
-- Nasm found. Activating nasm assembly.
-- Looking for include file getopt.h
-- Looking for include file getopt.h - found
-- Configuring done
-- Generating done
-- Build files have been written to: /home/user/VCA/build

I have built VCA in an Ubuntu 18.04 machine (GCC version 7.5.0) without any issues but I can't think of any reason why it's not working on my Arch.

gcc -v output:

$> gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-pc-linux-gnu/11.2.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /build/gcc/src/gcc/configure --enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++,d --enable-bootstrap --prefix=/usr --libdir=/usr/lib --libexecdir=/usr/lib --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=https://bugs.archlinux.org/ --with-linker-hash-style=gnu --with-system-zlib --enable-__cxa_atexit --enable-cet=auto --enable-checking=release --enable-clocale=gnu --enable-default-pie --enable-default-ssp --enable-gnu-indirect-function --enable-gnu-unique-object --enable-linker-build-id --enable-lto --enable-multilib --enable-plugin --enable-shared --enable-threads=posix --disable-libssp --disable-libstdcxx-pch --disable-werror --with-build-config=bootstrap-lto --enable-link-serialization=1 gdc_include_dir=/usr/include/dlang/gdc
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 11.2.0 (GCC)

g++ -v output:

$> g++ -v
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-pc-linux-gnu/11.2.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /build/gcc/src/gcc/configure --enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++,d --enable-bootstrap --prefix=/usr --libdir=/usr/lib --libexecdir=/usr/lib --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=https://bugs.archlinux.org/ --with-linker-hash-style=gnu --with-system-zlib --enable-__cxa_atexit --enable-cet=auto --enable-checking=release --enable-clocale=gnu --enable-default-pie --enable-default-ssp --enable-gnu-indirect-function --enable-gnu-unique-object --enable-linker-build-id --enable-lto --enable-multilib --enable-plugin --enable-shared --enable-threads=posix --disable-libssp --disable-libstdcxx-pch --disable-werror --with-build-config=bootstrap-lto --enable-link-serialization=1 gdc_include_dir=/usr/include/dlang/gdc
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 11.2.0 (GCC)

Distro: Archlinux cmake version 3.23.0 NASM version 2.15.05 gcc version 11.2.0

cd-athena / VCA

error: ‘size_t’ has not been declared while building #48