Fix $(AR) define, remove \u warns on macOS.

libagbsyscall/Makefile

@@ -6,7 +6,7 @@ COMPARE ?= 0
 # with when we want to use $(CC) to preprocess files
 # thus, manually create the variables for the bin
 # files, or use arm-none-eabi binaries on the system
-# if dkP is not installed on tihs system
+# if dkP is not installed on this system
 
 ifneq (,$(TOOLCHAIN))
 ifneq ($(wildcard $(TOOLCHAIN)/bin),)
@@ -17,8 +17,8 @@ endif
 PREFIX := arm-none-eabi-
 OBJCOPY := $(PREFIX)objcopy
 AS := $(PREFIX)as
-CPP := $(CC) -E
 LD := $(PREFIX)ld
+AR := $(PREFIX)ar
 
 # note: the makefile must be set up so MODERNCC is never called
 # if MODERN=0
@@ -30,6 +30,23 @@ else
 EXE :=
 endif
 
+# use arm-none-eabi-cpp for macOS
+# as macOS's default compiler is clang
+# and clang's preprocessor will warn on \u
+# when preprocessing asm files, expecting a unicode literal
+# we can't unconditionally use arm-none-eabi-cpp
+# as installations which install binutils-arm-none-eabi
+# don't come with it
+ifneq ($(MODERN),1)
+  ifeq ($(shell uname -s),Darwin)
+    CPP := $(PREFIX)cpp
+  else
+    CPP := $(CC) -E
+  endif
+else
+  CPP := $(PREFIX)cpp
+endif
+
 ASFLAGS := -mcpu=arm7tdmi
 ARFLAGS := rc