Failed to run make under tests

[laoshaw]

Describe the bug can not make tests

To Reproduce Steps to reproduce the behavior:

1. Go to tests
2. run 'make' on ubuntu 20.04
3. Scroll down to '....'
4. See error

cc -I.. -Wno-pointer-to-int-cast -Wno-int-to-pointer-cast -DSTB_DIVIDE_TEST ../stb_vorbis.c test_c_compilation.c test_c_lexer.c test_dxt.c test_easyfont.c test_image.c test_image_write.c test_perlin.c test_sprintf.c test_truetype.c test_voxel.c -lm
cc -I.. -Wno-write-strings -DSTB_DIVIDE_TEST -std=c++0x test_cpp_compilation.cpp -lm -lstdc++
/usr/bin/ld: /usr/lib/gcc/x86_64-linux-gnu/9/../../../x86_64-linux-gnu/Scrt1.o: in function `_start':
(.text+0x24): undefined reference to `main'
collect2: error: ld returned 1 exit status
make: *** [Makefile:10: all] Error 1

Expected behavior should build tests without errors

Screenshots If applicable, add screenshots to help explain your problem.

[hikari-no-yume]

I get this too, but on macOS. It's not clear to me if there's meant to be a main function and it's broken for some reason, or if it's meant to be a library and some systems don't require a special flag to compile one.

[rygorous]

Neither, this file as originally written is meant to be compiled but not linked into anything and the Makefile in question was submitted by a contributor and isn't (to my knowledge) used by the maintainers at all, or at least I've never used it. (This is the first time I'm learning about it even existing in the repository.)

[hikari-no-yume]

I'd be happy to contribute a small patch that fixes the Makefile so it won't try to link against main, but I am not a maintainer so I don't know if the file is reasonable to begin with. Does it look okay?

[rygorous]

I think all that needs to happen here is to add a -c to the line that compiles this file since the only reason the test_x_compilation file exist is to check that the libs compile when fed to a C/C++ compiler, respectively. (I.e. to test that the libs conform to the common subset of C and C++.)

[hikari-no-yume]

Might be good to compile them a few times with different language standards.

[nothings]

I believe the Makefile is part of the Travis integration, so probably shouldn't be touched unless that's broken.