Create makefile targets

Allow to change build target without modifiying the sources.
In order to keep compatibilty `sim` target is built by default.

src/main/c/emulator/makefile

@@ -12,6 +12,12 @@ SRCS = 	$(wildcard src/*.c) \
 
 LDSCRIPT = ${STANDALONE}/common/ram.ld
 
+sim: CFLAGS += -DSIM
+sim: all
+
+qemu: CFLAGS += -DQEMU
+qemu: all
+
 include ${STANDALONE}/common/riscv64-unknown-elf.mk
 include ${STANDALONE}/common/standalone.mk
 

src/main/c/emulator/src/config.h

@@ -1,9 +1,6 @@
 #ifndef CONFIG_H
 #define CONFIG_H
 
-//#define QEMU
-#define SIM
-
 #ifndef OS_CALL
 #define OS_CALL 0xC0000000
 #endif