GCC 7 support and cleanup compiler warnings

Makefile.rules

@@ -29,7 +29,7 @@ $(error RASPPI must be one of: 0, 1, 2, 3)
 endif
 
 AFLAGS	 += $(ARCH)
-CFLAGS	 += $(ARCH) -Wall -Wno-psabi -fsigned-char -fno-builtin -Ofast -DNDEBUG
+CFLAGS	 += $(ARCH) -Wall -Wno-unused-variable -Wno-unused-but-set-variable -Wno-psabi -fsigned-char -fno-builtin -Ofast -DNDEBUG
 CPPFLAGS := $(CFLAGS) $(CPPFLAGS) -fno-exceptions -fno-rtti -std=c++0x -Wno-write-strings
 CFLAGS	 += -fno-delete-null-pointer-checks -fdata-sections -ffunction-sections -u _printf_float -std=gnu99
 
@@ -45,4 +45,4 @@ CFLAGS	 += -fno-delete-null-pointer-checks -fdata-sections -ffunction-sections -
 
 %.o: %.cpp
 	@echo "  CPP  $@"
-	$(Q)$(CPP) $(CPPFLAGS) $(INCLUDE) -c -o $@ $<
+	$(Q)$(CPP) $(CPPFLAGS) $(INCLUDE) -c -o $@ $<

src/armc-cstartup.c

@@ -56,7 +56,7 @@ void _cstartup( unsigned int r0, unsigned int r1, unsigned int r2 )
     while( bss < bss_end )
         *bss++ = 0;
 
-	__libc_init_array();
+    __libc_init_array();
 
     /* We should never return from main ... */
     kernel_main( r0, r1, r2 );

src/armc-cstubs.c

@@ -87,6 +87,17 @@ void _exit(int status)
   }
 }
 
+void _fini(int status)
+{
+  /* Stop the compiler complaining about unused variables by "using" it */
+  (void) status;
+
+  while (1)
+  {
+    /* TRAP HERE */
+  }
+}
+
 /* There's currently no implementation of a file system because there's no
  file system! */
 int _close(int file)

src/iec_bus.h

@@ -531,10 +531,10 @@ public:
 		invertIECInputs = value;
 		if (value)
 		{
-			PI_Atn = ~PI_Atn;
-			PI_Data = ~PI_Data;
-			PI_Clock = ~PI_Clock;
-			PI_Reset = ~PI_Reset;
+			PI_Atn = !PI_Atn;
+			PI_Data = !PI_Data;
+			PI_Clock = !PI_Clock;
+			PI_Reset = !PI_Reset;
 		}
 	}
 
@@ -626,4 +626,4 @@ private:
 	static u32 inputRepeat[5];
 	static u32 inputRepeatPrev[5];
 };
-#endif
+#endif