Use sed instead of perl for replacements in Makefile.

Makefile

@@ -10,8 +10,6 @@ FLAGS += -Iinclude -Idep/include
 
 include arch.mk
 
-SED := perl -pi -e
-
 # Sources and build flags
 
 SOURCES += dep/nanovg/src/nanovg.c
@@ -27,6 +25,7 @@ FLAGS += -fPIC
 LDFLAGS += -shared
 
 ifdef ARCH_LIN
+	SED := sed -i
 	TARGET := libRack.so
 
 	SOURCES += dep/osdialog/osdialog_gtk3.c
@@ -47,6 +46,7 @@ build/dep/osdialog/osdialog_gtk3.c.o: FLAGS += $(shell pkg-config --cflags gtk+-
 endif
 
 ifdef ARCH_MAC
+	SED := sed -i ''
 	TARGET := libRack.dylib
 
 	SOURCES += dep/osdialog/osdialog_mac.m
@@ -62,6 +62,7 @@ ifdef ARCH_MAC
 endif
 
 ifdef ARCH_WIN
+	SED := sed -i
 	TARGET := libRack.dll
 
 	SOURCES += dep/osdialog/osdialog_win.c

dep.mk

@@ -10,7 +10,7 @@ DEP_FLAGS += -g -O3 -march=nocona
 # Static libs don't usually compiled with -fPIC, but since we're including them in a shared library, it's needed.
 DEP_FLAGS += -fPIC
 
-ifeq ($(ARCH), mac)
+ifdef ARCH_MAC
 	DEP_MAC_SDK_FLAGS := -mmacosx-version-min=10.7
 	DEP_FLAGS += $(DEP_MAC_SDK_FLAGS) -stdlib=libc++
 	DEP_LDFLAGS += $(DEP_MAC_SDK_FLAGS) -stdlib=libc++
@@ -35,12 +35,13 @@ CMAKE += -DCMAKE_INSTALL_LIBDIR=lib
 
 ifdef ARCH_MAC
 	SHA256SUM := shasum -a 256
+	SED := sed -i ''
 else
 	SHA256SUM := sha256sum
+	SED := sed -i
 endif
 SHA256 := sha256check() { echo "$$2  $$1" | $(SHA256SUM) -c; }; sha256check
 
-SED := perl -pi -e
 
 # Export environment for all dependency targets
 $(DEPS): export CFLAGS = $(DEP_CFLAGS)