build: add GZIP_COMPRESSION Make variable

Make gzip compression configurable for source, header, and binary
tarballs. Keep level 9 as the default.

Assisted-by: Codex
Signed-off-by: inoway46 <inoueyuya416@gmail.com>
PR-URL: #66228
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Filip Skokan <panva.ip@gmail.com>

Author: inoway46

Makefile

@@ -1137,6 +1137,7 @@ HAS_XZ ?= $(shell command -v xz > /dev/null 2>&1; [ $$? -eq 0 ] && echo 1 || ech
 SKIP_XZ ?= 0
 XZ = $(shell [ $(HAS_XZ) -eq 1 ] && [ $(SKIP_XZ) -eq 0 ] && echo 1 || echo 0)
 XZ_COMPRESSION ?= 9e
+GZIP_COMPRESSION ?= 9
 PKG=$(TARNAME).pkg
 MACOSOUTDIR=out/macos
 
@@ -1369,7 +1370,7 @@ endif
 	find $(TARNAME)/ -type l | xargs $(RM)
 	tar -cf $(TARNAME).tar $(TARNAME)
 	$(RM) -r $(TARNAME)
-	gzip -c -f -9 $(TARNAME).tar > $(TARNAME).tar.gz
+	gzip -c -f -$(GZIP_COMPRESSION) $(TARNAME).tar > $(TARNAME).tar.gz
 ifeq ($(XZ), 1)
 	xz -c -f -$(XZ_COMPRESSION) $(TARNAME).tar > $(TARNAME).tar.xz
 endif
@@ -1414,7 +1415,7 @@ $(TARBALL)-headers: release-only
 	find $(TARNAME)/ -type l | xargs $(RM)
 	tar -cf $(TARNAME)-headers.tar $(TARNAME)
 	$(RM) -r $(TARNAME)
-	gzip -c -f -9 $(TARNAME)-headers.tar > $(TARNAME)-headers.tar.gz
+	gzip -c -f -$(GZIP_COMPRESSION) $(TARNAME)-headers.tar > $(TARNAME)-headers.tar.gz
 ifeq ($(XZ), 1)
 	xz -c -f -$(XZ_COMPRESSION) $(TARNAME)-headers.tar > $(TARNAME)-headers.tar.xz
 endif
@@ -1459,7 +1460,7 @@ ifeq ($(OSTYPE),darwin)
 endif
 	tar -cf $(BINARYNAME).tar $(BINARYNAME)
 	$(RM) -r $(BINARYNAME)
-	gzip -c -f -9 $(BINARYNAME).tar > $(BINARYNAME).tar.gz
+	gzip -c -f -$(GZIP_COMPRESSION) $(BINARYNAME).tar > $(BINARYNAME).tar.gz
 ifeq ($(XZ), 1)
 	xz -c -f -$(XZ_COMPRESSION) $(BINARYNAME).tar > $(BINARYNAME).tar.xz
 endif