[openwrt/openwrt] rules.mk: add FILECMD variable

[LEDE Commits]

hauke pushed a commit to openwrt/openwrt.git, branch master:
https://git.openwrt.org/2bb8e4a88149e09389b409517219b4ade4e7578e

commit 2bb8e4a88149e09389b409517219b4ade4e7578e
Author: Michael Pratt <mcpratt at pm.me>
AuthorDate: Tue Mar 14 05:10:50 2023 -0400

    rules.mk: add FILECMD variable
    
    Some packages using Libtool have the possibility
    of using this environment variable if set,
    instead of the direct command for "file" using PATH,
    or the need to patch a hard-coded path.
    
    This is a new feature of Libtool 2.4.7
    
    Ref: bf261073d ("tools/libtool: bump to 2.4.7")
    Signed-off-by: Michael Pratt <mcpratt at pm.me>
---
 rules.mk | 1 +
 1 file changed, 1 insertion(+)

diff --git a/rules.mk b/rules.mk
index a2f5bcca4b..57d7995d4f 100644
--- a/rules.mk
+++ b/rules.mk
@@ -252,6 +252,7 @@ TARGET_NM:=$(TARGET_CROSS)gcc-nm
 TARGET_CC:=$(TARGET_CROSS)gcc
 TARGET_CXX:=$(TARGET_CROSS)g++
 KPATCH:=$(SCRIPT_DIR)/patch-kernel.sh
+FILECMD:=$(STAGING_DIR_HOST)/bin/file
 SED:=$(STAGING_DIR_HOST)/bin/sed -i -e
 ESED:=$(STAGING_DIR_HOST)/bin/sed -E -i -e
 MKHASH:=$(STAGING_DIR_HOST)/bin/mkhash