tools/resolve_btfids: Pass HOSTCFLAGS as EXTRA_CFLAGS to prepare targets

commit 2531ba0e4a upstream.

Thorsten reported build issue with command line that defined extra
HOSTCFLAGS that were not passed into 'prepare' targets, but were
used to build resolve_btfids objects.

This results in build fail when these objects are linked together:

  /usr/bin/ld: /build.../tools/bpf/resolve_btfids//libbpf/libbpf.a(libbpf-in.o):
  relocation R_X86_64_32 against `.rodata.str1.1' can not be used when making a PIE \
  object; recompile with -fPIE

Fixing this by passing HOSTCFLAGS in EXTRA_CFLAGS as part of
HOST_OVERRIDES variable for prepare targets.

[1] https://lore.kernel.org/bpf/f7922132-6645-6316-5675-0ece4197bfff@leemhuis.info/

Fixes: 56a2df7615 ("tools/resolve_btfids: Compile resolve_btfids as host program")
Reported-by: Thorsten Leemhuis <linux@leemhuis.info>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Thorsten Leemhuis <linux@leemhuis.info>
Acked-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/bpf/20230209143735.4112845-1-jolsa@kernel.org
Cc: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tools/bpf/resolve_btfids/Makefile

@@ -19,7 +19,7 @@ endif
 
 # Overrides for the prepare step libraries.
 HOST_OVERRIDES := AR="$(HOSTAR)" CC="$(HOSTCC)" LD="$(HOSTLD)" ARCH="$(HOSTARCH)" \
-		  CROSS_COMPILE=""
+		  CROSS_COMPILE="" EXTRA_CFLAGS="$(HOSTCFLAGS)"
 
 RM      ?= rm
 HOSTCC  ?= gcc