Allow specifying custom header declaration

The user can specify UNITY_OUTPUT_CHAR_HEADER_DECLARATION and
UNITY_OUTPUT_FLUSH_HEADER_DECLARATION when he would like to declare
UNITY_OUTPUT_CHAT or UNITY_OUTPUT_FLUSH respectivly

examples/unity_config.h

@@ -201,10 +201,12 @@
  * `stdout` option. You decide to route your test result output to a custom
  * serial `RS232_putc()` function you wrote like thus:
  */
-/* #define UNITY_OUTPUT_CHAR(a)    RS232_putc(a) */
-/* #define UNITY_OUTPUT_FLUSH()    RS232_flush() */
-/* #define UNITY_OUTPUT_START()    RS232_config(115200,1,8,0) */
-/* #define UNITY_OUTPUT_COMPLETE() RS232_close() */
+/* #define UNITY_OUTPUT_CHAR(a)                    RS232_putc(a) */
+/* #define UNITY_OUTPUT_CHAR_HEADER_DECLARATION    RS232_putc(int) */
+/* #define UNITY_OUTPUT_FLUSH()                    RS232_flush() */
+/* #define UNITY_OUTPUT_FLUSH_HEADER_DECLARATION   RS232_flush(void) */
+/* #define UNITY_OUTPUT_START()                    RS232_config(115200,1,8,0) */
+/* #define UNITY_OUTPUT_COMPLETE()                 RS232_close() */
 
 /* For some targets, Unity can make the otherwise required `setUp()` and
  * `tearDown()` functions optional. This is a nice convenience for test writers

src/unity_internals.h

@@ -246,8 +246,8 @@ typedef UNITY_FLOAT_TYPE UNITY_FLOAT;
 #define UNITY_OUTPUT_CHAR(a) (void)putchar(a)
 #else
   /* If defined as something else, make sure we declare it here so it's ready for use */
-  #ifndef UNITY_OMIT_OUTPUT_CHAR_HEADER_DECLARATION
-extern void UNITY_OUTPUT_CHAR(int);
+  #ifdef UNITY_OUTPUT_CHAR_HEADER_DECLARATION
+extern void UNITY_OUTPUT_CHAR_HEADER_DECLARATION;
   #endif
 #endif
 
@@ -255,22 +255,22 @@ extern void UNITY_OUTPUT_CHAR(int);
 #ifdef UNITY_USE_FLUSH_STDOUT
 /* We want to use the stdout flush utility */
 #include <stdio.h>
-#define UNITY_OUTPUT_FLUSH (void)fflush(stdout)
+#define UNITY_OUTPUT_FLUSH() (void)fflush(stdout)
 #else
 /* We've specified nothing, therefore flush should just be ignored */
-#define UNITY_OUTPUT_FLUSH
+#define UNITY_OUTPUT_FLUSH()
 #endif
 #else
 /* We've defined flush as something else, so make sure we declare it here so it's ready for use */
-#ifndef UNITY_OMIT_OUTPUT_FLUSH_HEADER_DECLARATION
-extern void UNITY_OUTPUT_FLUSH(void);
+#ifdef UNITY_OUTPUT_FLUSH_HEADER_DECLARATION
+extern void UNITY_OMIT_OUTPUT_FLUSH_HEADER_DECLARATION;
 #endif
 #endif
 
 #ifndef UNITY_OUTPUT_FLUSH
 #define UNITY_FLUSH_CALL()
 #else
-#define UNITY_FLUSH_CALL() UNITY_OUTPUT_FLUSH
+#define UNITY_FLUSH_CALL() UNITY_OUTPUT_FLUSH()
 #endif
 
 #ifndef UNITY_PRINT_EOL