This commit reduces our romsize by 3KB by optimizing away libc's malloc() function

The problem was that our custom_malloc was not marking these functions as extern "C".
Therefore libc's malloc function and everything linked to it was still getting pulled into our
rom.

Fix: mark these functions as extern "C". This ensures that these functions aren't getting pulled in
from libc. This reduces our rom size by 3KB

source/custom_malloc.cpp

@@ -201,6 +201,9 @@ void malloc_init_default_pool(void)
 	memset(g_alloc_map, 0, sizeof(g_alloc_map));  // Clear bitmap
 }
 
+extern "C"
+{
+
 /// @brief The custom implementation of the bitmap allocator described at the top of this module.
 void* malloc(size_t size)
 {
@@ -333,6 +336,8 @@ void _free_r(struct _reent *r, void* ptr) {
     return free(ptr);
 }
 
+}
+
 #else
 
 void malloc_init_default_pool(void)