fix for: Result of 'realloc' is converted to a pointer of type 'struct _patch *', which is incompatible with sizeof operand type 'struct _patch'
fix many issues: "Array access results in a null pointer dereference" and "Null pointer passed as an argument to a nonnull parameter"
handle warning from clang static analyzer:
src/wildmidi_lib.c:3767:16: warning: Value stored to 'note_data' during its initialization is never read
struct _note *note_data = mdi->note;
minor simplifications of line_tokens[1] == NULL to !line_tokens[1]
fix another clang static analyzer warning:
src/wildmidi_lib.c:3789:2: warning: Value stored to 'real_samples_to_mix' is never read
real_samples_to_mix = 0;
another clang static analyzer fix