[Jack & Erez] Adds an option for user-specific config.h files

tmk_core/rules.mk

@@ -142,6 +142,9 @@ CFLAGS += $(CSTANDARD)
 ifdef CONFIG_H
     CFLAGS += -include $(CONFIG_H)
 endif
+ifdef CONFIG_USER_H
+    CFLAGS += -include $(CONFIG_USER_H)
+endif
 
 
 #---------------- Compiler Options C++ ----------------
@@ -176,6 +179,9 @@ CPPFLAGS += $(patsubst %,-I%,$(EXTRAINCDIRS))
 ifdef CONFIG_H
     CPPFLAGS += -include $(CONFIG_H)
 endif
+ifdef CONFIG_USER_H
+    CPPFLAGS += -include $(CONFIG_USER_H)
+endif
 
 
 #---------------- Assembler Options ----------------
@@ -192,6 +198,9 @@ ASFLAGS += $(patsubst %,-I%,$(EXTRAINCDIRS))
 ifdef CONFIG_H
     ASFLAGS += -include $(CONFIG_H)
 endif
+ifdef CONFIG_USER_H
+    ASFLAGS += -include $(CONFIG_USER_H)
+endif
 
 
 #---------------- Library Options ----------------