linuxHeaders: 4.19.16 -> 5.5

Linux has reworked its header install process in
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=59b2bd05f5f4dc62979c2e82ddd384f07e8f10bc
It has introduced `make headers` that prepares the headers in ./usr/include, and
made `make headers_install` copy the headers from there using rsync.

pkgs/os-specific/linux/kernel-headers/no-relocs.patch

@@ -1,13 +1,7 @@
-diff --git a/arch/x86/Makefile b/arch/x86/Makefile
-index fad55160dcb9..a48c8331cbb2 100644
 --- a/arch/x86/Makefile
 +++ b/arch/x86/Makefile
-@@ -239,7 +239,7 @@ ifdef CONFIG_RETPOLINE
- endif
- 
+@@ -231,3 +231,3 @@ endif
  archscripts: scripts_basic
 -	$(Q)$(MAKE) $(build)=arch/x86/tools relocs
 +	$(Q)$(MAKE) $(build)=arch/x86/tools
  
- ###
- # Syscall table generation