Thanks! I wanted to this a couple of times but always forgot to do it... :-)

This seems to have broken my build on arch linux:

G-C-.o: In function `*GC::stats:GC::Stats':
GC:(.text+0x419): undefined reference to `GC_bytes_found'
collect2: error: ld returned 1 exit status
Error: execution of command failed with code: 1: `cc -o "/data/programming/crystal/.build/std_spec" "${@}"  -rdynamic  -lyaml `/usr/bin/llvm-config --libs --system-libs --ldflags 2> /dev/null` -lstdc++ `command -v pkg-config > /dev/null && pkg-config --libs libssl || printf %s '-lssl -lcrypto'` `command -v pkg-config > /dev/null && pkg-config --libs libcrypto || printf %s '-lcrypto'` -lz -lreadline -lgmp -lxml2 -lpcre -lm -lgc -lpthread /data/programming/crystal/src/ext/libcrystal.a -levent -lrt -ldl -L/usr/lib -L/usr/local/lib`

It seems from the source as if GC_bytes_found is a private variable inside bdwgc, so i'm not sure if we should reply on it being present.

Seems as if the core issue is that the arch package is built with --disable-static, which hides private symbols, of which GC_bytes_found is one. So I don't think it's appropriate to use.

bytes_found was before this commit, and also this is strange value not showing anything, i think need to delete it.

@kostya but it didn't have a spec before this commit, so .stats was never called, and so the symbol didn't make it into the binary for the linker to error at.

This is #837 again, but with a different symbol from LibGC.

Don't worry, we'll eventually provide our own LibGC fork because we already made some changes to it to support multiple threads, so these functions will be available everywhere.

@asterite how am I meant to contribute to crystal in the meantime? Revert the commit every time I need to run specs, and unrevert every time I need to push? The point is that we're using LibGC's internal API, and that's not portable.

I see. We can probably remove stats then and someone can provide it as a temporary shard.

@RX14 Let me know if it compiles now. I think GC_get_heap_usage_safe is exposed, and that's the only thing used now.