fedora f44: rocm: build fails to find libstdc++

In order to build using ROCm on Fedora F44, I had to do the following:

1. Symlink /usr/lib64/libstdc++.so.6 to /usr/lib64/libstdc++.so (to fix a hipcc error where it couldn't link `-lstdc++`)
2. Modify `GPU_LD_LIBS = GPU_LDLIBS = -lm -pthread -L$(ROCM_PATH)/lib64 -lhipblas -lamdhip64` (the libraries are under /lib64, and it wasn't linking libamdhip64)
3. Modify `CFLAGS ?= -O3 -ffast-math $(NATIVE_CPU_FLAG) -Wall -Wextra -std=c99 -fPIC` (it was compiling without `-fPIC`, which didn't work)

Aside from that, it was a lot of installing various packages as required, then building with:

```
make rocm ROCM_ARCH=gfx1151 ROCM_PATH=/usr
```