Failed to generate pnglibconf.tf5 error with SDL_image in WSL - c++

Question

I am trying to build a simple project using SDL and SDL_image. Both are added as submodules.
On Windows it compiles without issues. Under WSL (Ubuntu 20.04) I get this error:
[ 61%] Building C object submodules/SDL/CMakeFiles/SDL2.dir/src/sensor/dummy/SDL_dummysensor.c.o
[ 62%] Linking C shared library ../../lib/libSDL2-2.0.so
[ 62%] Built target SDL2
Scanning dependencies of target SDL2main
[ 63%] Building C object submodules/SDL/CMakeFiles/SDL2main.dir/src/main/dummy/SDL_dummy_main.c.o
[ 63%] Linking C static library ../../lib/libSDL2main.a
[ 63%] Built target SDL2main
Scanning dependencies of target genfiles
[ 63%] Generating pnglibconf.c
options.awk: bad line (10): com
CMake Error at scripts/gensrc.cmake:68 (message):
Failed to generate pnglibconf.tf5
make[2]: *** [submodules/SDL_image/external/libpng-1.6.37/CMakeFiles/genfiles.dir/build.make:85: submodules/SDL_image/external/libpng-1.6.37/pnglibconf.c] Error 1
make[1]: *** [CMakeFiles/Makefile2:835: submodules/SDL_image/external/libpng-1.6.37/CMakeFiles/genfiles.dir/all] Error 2
make: *** [Makefile:141: all] Error 2
My root CMakeLists.txt:
cmake_minimum_required(VERSION 3.16)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(PROJECT_NAME SDL_Starter_package)
set(PROJECT_TESTS_NAME SDL_Starter_package_tests)
project(${PROJECT_NAME} VERSION 1.0.0)
set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)
set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
include_directories(submodules/googletest/googletest/include/gtest)
include_directories(submodules/SDL/include)
include_directories(submodules/SDL_image)
add_subdirectory(submodules/googletest)
add_subdirectory(submodules/SDL)
add_subdirectory(submodules/SDL_image)
include_directories(src)
add_subdirectory(src)
if(BUILD_TESTS)
enable_testing()
add_subdirectory(tests)
endif()
What am I missing? Is it something because I use WSL?