[openwrt/openwrt] build: make testing kernel decompression more portable

[LEDE Commits]

nbd pushed a commit to openwrt/openwrt.git, branch master:
https://git.openwrt.org/ef11309c22fae2fb27e8c32163b5ca274468e82e

commit ef11309c22fae2fb27e8c32163b5ca274468e82e
Author: Felix Fietkau <nbd at nbd.name>
AuthorDate: Thu Nov 26 16:12:12 2020 +0100

    build: make testing kernel decompression more portable
    
    On non-GNU systems, zcat often does not handle gzip decompression.
    Use gzip -dc like the regular unpack command
    
    Signed-off-by: Felix Fietkau <nbd at nbd.name>
---
 include/kernel-defaults.mk | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/kernel-defaults.mk b/include/kernel-defaults.mk
index db93a53d71..863c180e48 100644
--- a/include/kernel-defaults.mk
+++ b/include/kernel-defaults.mk
@@ -24,7 +24,7 @@ Kernel/Patch:=$(Kernel/Patch/Default)
 ifneq (,$(findstring .xz,$(LINUX_SOURCE)))
   LINUX_CAT:=xzcat
 else
-  LINUX_CAT:=zcat
+  LINUX_CAT:=gzip -dc
 endif
 
 ifeq ($(strip $(CONFIG_EXTERNAL_KERNEL_TREE)),"")