Use make functions to convert a text to lower case
We cannot cache the result of ($shell ...) and we have to run these on
every build even if we don't have to re-read the makefiles. Replace it
with make functions $(substr $(substr ... )).
Bug: 38399657
Test: `make` pass, flash images from $OUT and boot device with chain partitions
Change-Id: I6d4ff8e487931ba25008a2a881401a8951d4049e
diff --git a/core/Makefile b/core/Makefile
index 64a5bc6..a8eb7c2 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -1773,6 +1773,12 @@
endif
+# Convert to lower case without requiring a shell, which isn't cacheable.
+to-lower = $(subst A,a,$(subst B,b,$(subst C,c,$(subst D,d,$(subst E,e,$(subst F,f,$(subst G,g,\
+$(subst H,h,$(subst I,i,$(subst J,j,$(subst K,k,$(subst L,l,$(subst M,m,$(subst N,n,$(subst O,o,\
+$(subst P,p,$(subst Q,q,$(subst R,r,$(subst S,s,$(subst T,t,$(subst U,u,$(subst V,v,$(subst W,w,\
+$(subst X,x,$(subst Y,y,$(subst Z,z,$1))))))))))))))))))))))))))
+
# -----------------------------------------------------------------
# vbmeta image
ifeq ($(BOARD_AVB_ENABLE),true)
@@ -1800,7 +1806,7 @@
# $(1): the partition to enable AVB chain, e.g., BOOT or SYSTEM.
define check-and-set-avb-chain-args
$(eval PART := $(1))
-$(eval part=$(shell echo $(PART) | tr A-Z a-z))
+$(eval part=$(call to-lower,$(PART)))
$(eval _key_path := BOARD_AVB_$(PART)_KEY_PATH)
$(eval _signing_algorithm := BOARD_AVB_$(PART)_ALGORITHM)
