Fix Raspberry Pi Compilation

Reported by @Torom over discord.

> dev build fails on Raspberry Pi 5 with clang

```
clang++ -o stockfish benchmark.o bitboard.o evaluate.o main.o misc.o movegen.o movepick.o position.o search.o thread.o timeman.o tt.o uci.o ucioption.o tune.o tbprobe.o nnue_misc.o half_ka_v2_hm.o network.o  -fprofile-instr-generate -latomic -lpthread  -Wall -Wcast-qual -fno-exceptions -std=c++17 -fprofile-instr-generate  -pedantic -Wextra -Wshadow -Wmissing-prototypes -Wconditional-uninitialized -DUSE_PTHREADS -DNDEBUG -O3 -funroll-loops -DIS_64BIT -DUSE_POPCNT -DUSE_NEON=8 -march=armv8.2-a+dotprod -DUSE_NEON_DOTPROD -DGIT_SHA=627974c9 -DGIT_DATE=20240312 -DARCH=armv8-dotprod -flto=full
/tmp/lto-llvm-e9300e.o: in function `_GLOBAL__sub_I_network.cpp':
ld-temp.o:(.text.startup+0x704c): relocation truncated to fit: R_AARCH64_LDST64_ABS_LO12_NC against symbol `gEmbeddedNNUEBigEnd' defined in .rodata section in /tmp/lto-llvm-e9300e.o
/usr/bin/ld: ld-temp.o:(.text.startup+0x704c): warning: one possible cause of this error is that the symbol is being referenced in the indicated code as if it had a larger alignment than was declared where it was defined
ld-temp.o:(.text.startup+0x7068): relocation truncated to fit: R_AARCH64_LDST64_ABS_LO12_NC against symbol `gEmbeddedNNUESmallEnd' defined in .rodata section in /tmp/lto-llvm-e9300e.o
/usr/bin/ld: ld-temp.o:(.text.startup+0x7068): warning: one possible cause of this error is that the symbol is being referenced in the indicated code as if it had a larger alignment than was declared where it was defined
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[2]: *** [Makefile:1051: stockfish] Error 1
make[2]: Leaving directory '/home/torsten/chess/Stockfish_master/src'
make[1]: *** [Makefile:1058: clang-profile-make] Error 2
make[1]: Leaving directory '/home/torsten/chess/Stockfish_master/src'
make: *** [Makefile:886: profile-build] Error 2
```

closes https://github.com/official-stockfish/Stockfish/pull/5106

No functional change

src/Makefile

@@ -502,7 +502,7 @@ endif
 # In earlier NDK versions, you'll need to pass -fno-addrsig if using GNU binutils.
 # Currently we don't know how to make PGO builds with the NDK yet.
 ifeq ($(COMP),ndk)
-	CXXFLAGS += -stdlib=libc++ -fPIE -mcmodel=large
+	CXXFLAGS += -stdlib=libc++ -fPIE
 	comp=clang
 	ifeq ($(arch),armv7)
 		CXX=armv7a-linux-androideabi16-clang++

src/nnue/network.cpp

@@ -55,15 +55,33 @@ const unsigned char        gEmbeddedNNUESmallData[1] = {0x0};
 const unsigned char* const gEmbeddedNNUESmallEnd     = &gEmbeddedNNUESmallData[1];
 const unsigned int         gEmbeddedNNUESmallSize    = 1;
 #endif
+
+struct EmbeddedNNUE {
+    EmbeddedNNUE(const unsigned char* embeddedData,
+                 const unsigned char* embeddedEnd,
+                 const unsigned int   embeddedSize) :
+        data(embeddedData),
+        end(embeddedEnd),
+        size(embeddedSize) {}
+    const unsigned char* data;
+    const unsigned char* end;
+    const unsigned int   size;
+};
+
+using namespace Stockfish::Eval::NNUE;
+
+EmbeddedNNUE get_embedded(EmbeddedNNUEType type) {
+    if (type == EmbeddedNNUEType::BIG)
+        return EmbeddedNNUE(gEmbeddedNNUEBigData, gEmbeddedNNUEBigEnd, gEmbeddedNNUEBigSize);
+    else
+        return EmbeddedNNUE(gEmbeddedNNUESmallData, gEmbeddedNNUESmallEnd, gEmbeddedNNUESmallSize);
+}
+
 }
 
 
 namespace Stockfish::Eval::NNUE {
 
-const EmbeddedNNUE embeddedNNUEBig(gEmbeddedNNUEBigData, gEmbeddedNNUEBigEnd, gEmbeddedNNUEBigSize);
-const EmbeddedNNUE
-  embeddedNNUESmall(gEmbeddedNNUESmallData, gEmbeddedNNUESmallEnd, gEmbeddedNNUESmallSize);
-
 
 namespace Detail {
 
@@ -302,6 +320,8 @@ void Network<Arch, Transformer>::load_internal() {
         }
     };
 
+    const auto embedded = get_embedded(embeddedType);
+
     MemoryBuffer buffer(const_cast<char*>(reinterpret_cast<const char*>(embedded.data)),
                         size_t(embedded.size));
 

src/nnue/network.h

@@ -34,27 +34,19 @@
 
 namespace Stockfish::Eval::NNUE {
 
-struct EmbeddedNNUE {
-    EmbeddedNNUE(const unsigned char* embeddedData,
-                 const unsigned char* embeddedEnd,
-                 const unsigned int   embeddedSize) :
-        data(embeddedData),
-        end(embeddedEnd),
-        size(embeddedSize) {}
-    const unsigned char* data;
-    const unsigned char* end;
-    const unsigned int   size;
+
+enum class EmbeddedNNUEType {
+    BIG,
+    SMALL,
 };
 
-extern const EmbeddedNNUE embeddedNNUEBig;
-extern const EmbeddedNNUE embeddedNNUESmall;
 
 template<typename Arch, typename Transformer>
 class Network {
    public:
-    Network(EvalFile file, EmbeddedNNUE embeddedEval) :
+    Network(EvalFile file, EmbeddedNNUEType type) :
         evalFile(file),
-        embedded(embeddedEval) {}
+        embeddedType(type) {}
 
     void load(const std::string& rootDirectory, std::string evalfilePath);
     bool save(const std::optional<std::string>& filename) const;
@@ -92,8 +84,8 @@ class Network {
     // Evaluation function
     AlignedPtr<Arch> network[LayerStacks];
 
-    EvalFile     evalFile;
-    EmbeddedNNUE embedded;
+    EvalFile         evalFile;
+    EmbeddedNNUEType embeddedType;
 
     // Hash value of evaluation function structure
     static constexpr std::uint32_t hash = Transformer::get_hash_value() ^ Arch::get_hash_value();

src/uci.cpp

@@ -54,8 +54,8 @@ namespace NN = Eval::NNUE;
 
 UCI::UCI(int argc, char** argv) :
     networks(NN::Networks(
-      NN::NetworkBig({EvalFileDefaultNameBig, "None", ""}, NN::embeddedNNUEBig),
-      NN::NetworkSmall({EvalFileDefaultNameSmall, "None", ""}, NN::embeddedNNUESmall))),
+      NN::NetworkBig({EvalFileDefaultNameBig, "None", ""}, NN::EmbeddedNNUEType::BIG),
+      NN::NetworkSmall({EvalFileDefaultNameSmall, "None", ""}, NN::EmbeddedNNUEType::SMALL))),
     cli(argc, argv) {
 
     options["Debug Log File"] << Option("", [](const Option& o) { start_logger(o); });