Compile fails on ARM, and furthermore on OSX

[struthiocamelus]

• Compile fails on all ARM platforms due to the mere presence of ResamplerAVX2. CMake should filter out the AVX2 resampler when compiling for ARM and the inclusion of the file should be gated by a macro.
• clang complains loudly about something I don't understand having to do with std::thread - it's possible clang doesn't play well with whatever the namespace std { class thread; } thing going on at the head of MainWindow.hpp is doing.

[ArcaneNibble]

I was able to build on (a rather old version of) macOS on ARM with the following patch

diff --git a/src/agbplay-gui/MainWindow.hpp b/src/agbplay-gui/MainWindow.hpp
index f77c2b2..a47c878 100644
--- a/src/agbplay-gui/MainWindow.hpp
+++ b/src/agbplay-gui/MainWindow.hpp
@@ -22,10 +22,10 @@ class PlaybackEngine;
 class ProfileManager;
 struct Settings;
 struct Profile;
-namespace std
-{
-    class thread;
-}
+// namespace std
+// {
+//     class thread;
+// }
 struct MP2KVisualizerState;
 
 class MainWindow : public QMainWindow
diff --git a/src/agbplay-gui/ProfileSettingsWindow.cpp b/src/agbplay-gui/ProfileSettingsWindow.cpp
index 015421c..4137065 100644
--- a/src/agbplay-gui/ProfileSettingsWindow.cpp
+++ b/src/agbplay-gui/ProfileSettingsWindow.cpp
@@ -2,6 +2,7 @@
 
 #include "ui_ProfileSettingsWindow.h"
 
+#include <fmt/core.h>
 #include <QAbstractButton>
 #include <QFileDialog>
 #include <QMessageBox>
@@ -255,7 +256,7 @@ void ProfileSettingsWindow::InitSoundMode()
     };
 
     for (unsigned int i = 0; i < sampleRates.size(); i++)
-        ui->comboBoxFreq->addItem(QString::fromStdString(std::format("{} Hz", sampleRates.at(i))), i + 1);
+        ui->comboBoxFreq->addItem(QString::fromStdString(fmt::format("{} Hz", sampleRates.at(i))), i + 1);
 
     if (profile->mp2kSoundModeConfig.freq == MP2KSoundMode::FREQ_AUTO) {
         assert(profile->mp2kSoundModePlayback.freq > 0);
@@ -582,7 +583,7 @@ void ProfileSettingsWindow::InitGameTables()
             ui->tableWidgetPlayers->insertRow(row);
             ui->tableWidgetPlayers->setItem(row, COL_PLT_TRACKS, new QTableWidgetItem(QString::number(plt.at(i).maxTracks)));
             ui->tableWidgetPlayers->setItem(row, COL_PLT_PRIO, new QTableWidgetItem(QString::number(plt.at(i).usePriority)));
-            ui->tableWidgetPlayers->setVerticalHeaderItem(row, new QTableWidgetItem(QString::fromStdString(std::format("Player {}", row))));
+            ui->tableWidgetPlayers->setVerticalHeaderItem(row, new QTableWidgetItem(QString::fromStdString(fmt::format("Player {}", row))));
         }
     };
 
@@ -608,7 +609,7 @@ void ProfileSettingsWindow::InitGameTables()
         ui->tableWidgetPlayers->insertRow(row);
         ui->tableWidgetPlayers->setItem(row, COL_PLT_TRACKS, new QTableWidgetItem("16")); // TODO replace 16 with constant
         ui->tableWidgetPlayers->setItem(row, COL_PLT_PRIO, new QTableWidgetItem("0"));
-        ui->tableWidgetPlayers->setVerticalHeaderItem(row, new QTableWidgetItem(QString::fromStdString(std::format("Player {}", row))));
+        ui->tableWidgetPlayers->setVerticalHeaderItem(row, new QTableWidgetItem(QString::fromStdString(fmt::format("Player {}", row))));
         MarkPending();
     });
 
@@ -685,7 +686,7 @@ void ProfileSettingsWindow::InitProfileAssignment()
     /* magic bytes */
     QStringList byteStringList;
     for (uint8_t byte : profile->gameMatch.magicBytes)
-        byteStringList << QString::fromStdString(std::format("{:02X}", byte));
+        byteStringList << QString::fromStdString(fmt::format("{:02X}", byte));
     ui->lineEditMagicBytes->setText(byteStringList.join(" "));
     prevMagicBytes = ui->lineEditMagicBytes->text();
 
@@ -829,7 +830,7 @@ void ProfileSettingsWindow::Apply()
             QTableWidgetItem *usePrioItem = ui->tableWidgetPlayers->item(row, COL_PLT_PRIO);
             const uint8_t maxTracks = static_cast<uint8_t>(maxTracksItem->text().toInt());
             const uint8_t usePrio = static_cast<uint8_t>(usePrioItem->text().toInt());
-            profile->playerTableConfig.emplace_back(maxTracks, usePrio);
+            profile->playerTableConfig.emplace_back(PlayerInfo {maxTracks, usePrio});
         }
     } else {
         profile->playerTableConfig.clear();
diff --git a/src/agbplay/LowLatencyRingbuffer.cpp b/src/agbplay/LowLatencyRingbuffer.cpp
index aa34f37..df11450 100644
--- a/src/agbplay/LowLatencyRingbuffer.cpp
+++ b/src/agbplay/LowLatencyRingbuffer.cpp
@@ -139,9 +139,9 @@ void LowLatencyRingbuffer::IncreaseBufferSize(size_t requiredBufferSize)
      * (unless the chunk sizes increase once again). */
     std::vector<sample> backupBuffer(dataCount);
     const size_t beforeWraparoundSize = std::min<size_t>(dataCount, buffer.size() - dataPos);
-    std::span<sample> beforeWraparound(buffer.begin() + dataPos, beforeWraparoundSize);
+    // std::span<sample> beforeWraparound(buffer.begin() + dataPos, beforeWraparoundSize);
     const size_t afterWraparoundSize = dataCount - beforeWraparoundSize;
-    std::span<sample> afterWraparound(buffer.begin(), afterWraparoundSize);
+    // std::span<sample> afterWraparound(buffer.begin(), afterWraparoundSize);
     std::copy_n(buffer.begin() + dataPos, beforeWraparoundSize, backupBuffer.begin());
     std::copy_n(buffer.begin(), afterWraparoundSize, backupBuffer.begin() + beforeWraparoundSize);
     assert(beforeWraparoundSize + afterWraparoundSize == dataCount);
diff --git a/src/agbplay/ResamplerAVX2.cpp b/src/agbplay/ResamplerAVX2.cpp
index f731c81..cec6420 100644
--- a/src/agbplay/ResamplerAVX2.cpp
+++ b/src/agbplay/ResamplerAVX2.cpp
@@ -1,3 +1,5 @@
+#if defined(__x86_64__) || defined(i386) || defined(__i386__) || defined(__386)
+
 #include "ResamplerAVX2.hpp"
 
 #include <cmath>
@@ -294,3 +296,5 @@ inline __m256 BlampResamplerAVX2::fast_Ti(__m256 t)
     const __m256 isOutOfRange = _mm256_cmp_ps(old_t, _mm256_set1_ps(float(INTERP_FILTER_SIZE)), _CMP_GT_OS);
     return _mm256_or_ps(_mm256_andnot_ps(isOutOfRange, retval), _mm256_and_ps(isOutOfRange, outOfRangeRetval));
 }
+
+#endif
diff --git a/src/agbplay/ResamplerAVX2.hpp b/src/agbplay/ResamplerAVX2.hpp
index b9a8a68..f49e82e 100644
--- a/src/agbplay/ResamplerAVX2.hpp
+++ b/src/agbplay/ResamplerAVX2.hpp
@@ -2,7 +2,7 @@
 
 #include "Resampler.hpp"
 
-#if __has_include(<immintrin.h>)
+#if (defined(__x86_64__) || defined(i386) || defined(__i386__) || defined(__386)) && __has_include(<immintrin.h>)
 
 #include <immintrin.h>
 

This does the following:

1. Removes the declaration of std::thread which doesn't work on macOS. It seems to already be transitively included?
2. Changes a use of std::format to fmt::format
3. Fixes some C++20-related thing that I don't really understand, due to not being very familiar with C++
4. Removes some unused std::span which doesn't work for some reason
5. Disables trying to build AVX2 code