--- a/Makefile	2020-02-24 19:01:11.000000000 +0300
+++ b/Makefile	2020-03-08 03:07:40.480074095 +0300
@@ -66,11 +66,11 @@ endif
 #
 # -MMD to generate header dependencies.
 ifeq ($(OSTYPE), Darwin)
-CFLAGS := -O2 -fno-strict-aliasing -fomit-frame-pointer \
-		  -Wall -pipe -g -fwrapv -arch x86_64
+CFLAGS += -fno-strict-aliasing -fomit-frame-pointer \
+		  -Wall -fwrapv -arch x86_64
 else
-CFLAGS := -O2 -fno-strict-aliasing -fomit-frame-pointer \
-		  -Wall -pipe -g -MMD -fwrapv
+CFLAGS += -fno-strict-aliasing -fomit-frame-pointer \
+		  -Wall -MMD -fwrapv
 endif
 
 # ----------
@@ -93,11 +93,11 @@ endif
 
 # Base LDFLAGS.
 ifeq ($(OSTYPE), Darwin)
-LDFLAGS := -shared -arch x86_64
+LDFLAGS += -shared -arch x86_64
 else ifeq ($(OSTYPE), Windows)
-LDFLAGS := -shared -static-libgcc
+LDFLAGS += -shared -static-libgcc
 else
-LDFLAGS := -shared -lm
+LDFLAGS += -shared -lm
 endif
 
 # ----------