Define fpp_t and f_cnt_t to be of size_t (#7363)

Defines `fpp_t` and `f_cnt_t` to be of `size_t` within `lmms_basics.h`.  Most of the codebase used `fpp_t` to represent the size of an array of sample frames, which is incorrect, given that `fpp_t` was only 16 bits when sizes greater than 32767 are very possible. `f_cnt_t` was defined as `size_t` as well for consistency.

---------

Co-authored-by: Dominic Clark <mrdomclark@gmail.com>

include/InstrumentFunctions.h

@@ -25,11 +25,12 @@
 #ifndef LMMS_INSTRUMENT_FUNCTIONS_H
 #define LMMS_INSTRUMENT_FUNCTIONS_H
 
-#include "JournallingObject.h"
-#include "lmms_basics.h"
+#include <array>
+
 #include "AutomatableModel.h"
-#include "TempoSyncKnobModel.h"
 #include "ComboBoxModel.h"
+#include "JournallingObject.h"
+#include "TempoSyncKnobModel.h"
 
 namespace lmms
 {

include/Piano.h

@@ -25,8 +25,10 @@
 #ifndef LMMS_PIANO_H
 #define LMMS_PIANO_H
 
-#include "Note.h"
+#include <array>
+
 #include "Model.h"
+#include "Note.h"
 
 namespace lmms
 {

include/SampleFrame.h

@@ -28,8 +28,9 @@
 
 #include "lmms_basics.h"
 
+#include <algorithm>
 #include <array>
-#include <cstddef>
+#include <cmath>
 
 
 namespace lmms

include/lmms_basics.h

@@ -31,10 +31,7 @@
 #include "lmmsconfig.h"
 
 #include <cstdint>
-#include <array>
 
-#include <cmath>
-#include <algorithm>
 
 
 namespace lmms
@@ -49,8 +46,8 @@ using sample_t = float;		  // standard sample-type
 using int_sample_t = int16_t; // 16-bit-int-sample
 
 using sample_rate_t = uint32_t; // sample-rate
-using fpp_t = int16_t;			// frames per period (0-16384)
-using f_cnt_t = int32_t;		// standard frame-count
+using fpp_t = size_t;			// frames per period (0-16384)
+using f_cnt_t = size_t;			// standard frame-count
 using ch_cnt_t = uint8_t;		// channel-count (0-DEFAULT_CHANNELS)
 using bpm_t = uint16_t;			// tempo (MIN_BPM to MAX_BPM)
 using bitrate_t = uint16_t;		// bitrate in kbps