COPY_HEADERS causing BTF errors

[jmontleon]

The COPY_HEADERS lines like below added in Makefiles are breaking BTF.

linux-stable/drivers/memory/eswin/es_dev_buf/Makefile

Line 4 in 5088af9

COPY_HEADERS:=$(shell cp $(ES_DEV_DMA_BUF_HEADER)/*.h include/linux)

To reproduce enable BTF options:

CONFIG_DEBUG_INFO_BTF=y
CONFIG_PAHOLE_HAS_SPLIT_BTF=y
CONFIG_DEBUG_INFO_BTF_MODULES=y
CONFIG_PROBE_EVENTS_BTF_ARGS=y

Then build the kernel and modules.
Copying the headers in place when make Image.gz is run causes vmlinux to get rebuilt when make modules is run and results in errors when loading any modules:

[  403.886685] BPF: [128333] FUNC  
[  403.889941] BPF: type_id=128305
[  403.893098] BPF:  
[  403.895117] BPF: Invalid name
[  403.898094] BPF: 
[  403.900029] failed to validate module [zram] BTF: -22