diff --git a/Arduino.mk b/Arduino.mk
index f55fd87..a238fe6 100644
--- a/Arduino.mk
+++ b/Arduino.mk
@@ -1047,11 +1047,17 @@ else
 endif
 
 # Using += instead of =, so that CPPFLAGS can be set per sketch level
-CPPFLAGS      += -$(MCU_FLAG_NAME)=$(MCU) -DF_CPU=$(F_CPU) -DARDUINO=$(ARDUINO_VERSION) $(ARDUINO_ARCH_FLAG) -D__PROG_TYPES_COMPAT__ \
+CPPFLAGS      += -$(MCU_FLAG_NAME)=$(MCU) -DF_CPU=$(F_CPU) -DARDUINO=$(ARDUINO_VERSION) $(ARDUINO_ARCH_FLAG) \
         -I$(ARDUINO_CORE_PATH) -I$(ARDUINO_VAR_PATH)/$(VARIANT) \
         $(SYS_INCLUDES) $(PLATFORM_INCLUDES) $(USER_INCLUDES) -Wall -ffunction-sections \
         -fdata-sections
 
+# PROG_TYPES_COMPAT is enabled by default for compatibility with the Arduino IDE.
+# By placing it before the user-provided CPPFLAGS rather than after, we allow the
+# the user to disable it if they like, by adding the negation of the flag
+# (-U__PROG_TYPES_COMPAT__) to the user-provided CPPFLAGS.
+CPPFLAGS := -D__PROG_TYPES_COMPAT__ $(CPPFLAGS)
+
 ifdef DEBUG
 OPTIMIZATION_FLAGS= $(DEBUG_FLAGS)
 else
diff --git a/HISTORY.md b/HISTORY.md
index b4f4200..434ed96 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -18,6 +18,7 @@ I tried to give credit whenever possible. If I have missed anyone, kindly add it
 - New: Add generation of tags file using ctags, which automatically includes project libs and Arduino core. (https://github.com/tuna-f1sh)
 - New: Add template Makefile and project boilerplate initialise script, `ardmk-init`. (https://github.com/tuna-f1sh)
 - New: Support atmelice_isp JTAG tool as ISP programmer. (https://github.com/tuna-f1sh)
+- New: Compatibility with deprecated pgmspace.h API can now be disabled since it sometimes causes bogus compiler warnings (issue #546)
 - New: Support Arduino ARM-based (SAM/SAMD) devices. (https://github.com/tuna-f1sh)
 
 ### 1.6.0 (2017-07-11)