EMCC_USE_NINJA seems to be ignoring cflags

[sbc100]

We had a bug recently where sdl3_ttf was failing to build, but it was not going up in CI because somehow EMCC_USE_NINJA was ignoring cflags:

With EMCC_USE_NINJA=1

$ EMCC_USE_NINJA=1 ./embuilder build sdl3_ttf --force
embuilder:INFO: building sdl3_ttf
embuilder: warning: sdl3 port is still experimental [-Wexperimental]
cache:INFO: generating port: sysroot/lib/wasm32-emscripten/libSDL3_ttf.a... (this will be cached in "/usr/local/google/home/sbc/dev/wasm/emscripten/cache/sysroot/lib/wasm32-emscripten/libSDL3_ttf.a" for subsequent builds)
cache:INFO:  - ok
embuilder:INFO: ...success. Took (0.00s)
ninja: Entering directory `/usr/local/google/home/sbc/dev/wasm/emscripten/cache/build'
[1/1] AR /usr/local/google/home/sbc/dev/wasm/emscripten/cache/sysroot/lib/wasm32-emscripten/libSDL3_ttf.a
embuilder:INFO: Built 1 targets in (0.17s)

Without:

$ ./embuilder build sdl3_ttf --force
embuilder:INFO: building sdl3_ttf
cache:INFO: deleting cached file: /usr/local/google/home/sbc/dev/wasm/emscripten/cache/sysroot/lib/wasm32-emscripten/libSDL3_ttf.a
embuilder: warning: sdl3 port is still experimental [-Wexperimental]
cache:INFO: generating port: sysroot/lib/wasm32-emscripten/libSDL3_ttf.a... (this will be cached in "/usr/local/google/home/sbc/dev/wasm/emscripten/cache/sysroot/lib/wasm32-emscripten/libSDL3_ttf.a" for subsequent builds)
emcc: error: sdl3 port is still experimental [-Wexperimental] [-Werror]
emcc: error: sdl3 port is still experimental [-Wexperimental] [-Werror]
emcc: error: sdl3 port is still experimental [-Wexperimental] [-Werror]
emcc: error: sdl3 port is still experimental [-Wexperimental] [-Werror]
emcc: error: sdl3 port is still experimental [-Wexperimental] [-Werror]
emcc: error: sdl3 port is still experimental [-Wexperimental] [-Werror]
embuilder: error: subprocess 1/6 failed (returned 1)! (cmdline: /usr/local/google/home/sbc/dev/wasm/emscripten/emcc -c /usr/local/google/home/sbc/dev/wasm/emscripten/cache/ports/sdl3_ttf/SDL_ttf-release-3.2.2/src/SDL_gpu_textengine.c -o /usr/local/google/home/sbc/dev/wasm/emscripten/cache/build/sdl3_ttf/wasm32_libSDL3_ttf/src/SDL_gpu_textengine.c.o -g -sSTRICT -Werror -ffile-prefix-map=/usr/local/google/home/sbc/dev/wasm/emscripten=/emsdk/emscripten -ffile-prefix-map=../../../..=/emsdk/emscripten -fdebug-compilation-dir=/emsdk/emscripten -O2 -I/usr/local/google/home/sbc/dev/wasm/emscripten/cache/ports/sdl3_ttf/SDL_ttf-release-3.2.2 -DTTF_USE_HARFBUZZ=1 -sUSE_SDL=3 -sUSE_FREETYPE -sUSE_HARFBUZZ)

[sbc100]

@dschuff maybe you know why this might happen?

[dschuff]

In this case it's ignoring the -Werror flag you mean?

[sbc100]

I didn't do any debugging, I just noticed the difference.

[sbc100]

But yes the build should fail in both configurations, not just one (You will need to revert #26452 to get the failure now though).