diff --git a/Makefile b/Makefile
index c9ae4493ddacc2edbd9bdbe7c874b7d48a768b75..5dd0f600bfd7bf760a7c4c6812c7b9e3e98f8c21 100644
--- a/Makefile
+++ b/Makefile
@@ -34,7 +34,7 @@ LIB_LC3PLUS  	?= liblc3plus.a
 LIB_LIBUTIL  	?= libivasutil.a
 
 # Default tool settings
-CC        ?= gcc
+CC        ?= clang
 RM        ?= rm -f
 AR        ?= ar
 
@@ -67,7 +67,6 @@ CFLAGS   += -std=c99 -pedantic -Wcast-qual -Wall -W -Wextra -Wno-long-long     \
             -Werror-implicit-function-declaration \
             -Wno-implicit-fallthrough -ffp-contract=off
 # to be uncommented in CI
-# CFLAGS += -Werror
 CFLAGS += -Winit-self
 CFLAGS += -Wunused-but-set-variable
 
@@ -132,7 +131,7 @@ LDFLAGS  += -Wl,-dead_strip
 endif
 endif
 
-OPTIM    ?= 0
+OPTIM    ?= 3
 CFLAGS   += -O$(OPTIM)
 
 CFLAGS   += $(foreach DIR,$(SRC_DIRS),-I$(DIR))