Provide an option not to auto-clean toolchain during daily-build (#11279)

Author: 0xba1a

toolkit/docs/building/building.md

@@ -589,6 +589,14 @@ also augment the URL list.
 
 > Use the daily build sources for the given date. `lkg` will use the last known good build.
 
+##### `DAILY_BUILD_SKIP_TOOLCHAIN_AUTO_CLEANUP=`**`n`** *(default)*
+
+> Delete the already downloaded toolchain RPMs and freshly download from LKG repo
+
+##### `DAILY_BUILD_SKIP_TOOLCHAIN_AUTO_CLEANUP=`**`y`**
+
+> Don't delete the already download tolchain RPMs to save time. Use only if are sure about this behaviour.
+
 #### `DISABLE_UPSTREAM_REPOS=...`
 
 ##### `DISABLE_UPSTREAM_REPOS=`**`n`** *(default)*

toolkit/scripts/daily_build.mk

@@ -24,6 +24,8 @@ DAILY_BUILD_ID ?=
 DAILY_BUILD_ID_UPDATE_MANIFESTS ?= y
 ##help:var:DAILY_BUILD_REPO={path to daily.repo}=Path to the daily build repo file to use.
 DAILY_BUILD_REPO ?=
+##help:var:DAILY_BUILD_SKIP_TOOLCHAIN_AUTO_CLEANUP={y,n}=Skip Deleting all downloaded toolchain RPMs when using a daily build.
+DAILY_BUILD_SKIP_TOOLCHAIN_AUTO_CLEANUP ?= n
 
 daily_lkg_workdir = $(BUILD_DIR)/daily_build_id
 

toolkit/scripts/toolchain.mk

@@ -94,8 +94,10 @@ clean-toolchain-rpms:
 # We leave the directory structure in place since docker based builds using re-usable chroots will have mounted the
 # toolchain subdirectories into the chroots. Removing the directories would break the mounts.
 $(STATUS_FLAGS_DIR)/toolchain_auto_cleanup.flag: $(STATUS_FLAGS_DIR)/daily_build_id.flag $(depend_VALIDATE_TOOLCHAIN_GPG)
+ifeq ($(SKIP_TOOLCHAIN_AUTO_CLEANUP),n)
 	@echo "Daily build ID or validation mode changed, sanitizing toolchain"
 	find $(TOOLCHAIN_RPMS_DIR) -type f -name '*.rpm' -exec rm -f {} +
+endif
 	touch $@
 
 copy-toolchain-rpms: