build: Fix a couple more warnings. (#3598)

src/core/libraries/fiber/fiber_context.s

@@ -118,4 +118,4 @@ _sceFiberSwitchEntry:
     # Fiber returned, not good
     movl $1, %edi
     call _sceFiberForceQuit
-    ret
+    ret

src/core/libraries/kernel/threads/exception.h

@@ -59,7 +59,7 @@ struct Mcontext {
     u64 mc_spare[6];
 };
 
-struct Stack {
+struct ExStack {
     void* ss_sp;
     std::size_t ss_size;
     int ss_flags;
@@ -75,7 +75,7 @@ struct Ucontext {
     int field1_0x10[12];
     struct Mcontext uc_mcontext;
     struct Ucontext* uc_link;
-    struct Stack uc_stack;
+    struct ExStack uc_stack;
     int uc_flags;
     int __spare[4];
     int field7_0x4f4[3];

src/core/libraries/libc_internal/printf.h

@@ -60,6 +60,7 @@
 #include <cstdint>
 #include <cstring>
 #include <string>
+#include <vector>
 
 #include "common/va_ctx.h"
 
@@ -745,17 +746,17 @@ static int fprintf_ctx(Common::VaCtx* ctx, char* buf) {
 }
 
 static int vsnprintf_ctx(char* s, size_t n, const char* format, Common::VaList* arg) {
-    char buffer[n];
-    int result = _vsnprintf(_out_buffer, buffer, format, arg);
-    std::strcpy(s, buffer);
+    std::vector<char> buffer(n);
+    int result = _vsnprintf(_out_buffer, buffer.data(), format, arg);
+    std::strcpy(s, buffer.data());
     return result;
 }
 
 static int snprintf_ctx(char* s, size_t n, Common::VaCtx* ctx) {
     const char* format = vaArgPtr<const char>(&ctx->va_list);
-    char buffer[n];
-    int result = _vsnprintf(_out_buffer, buffer, format, &ctx->va_list);
-    std::strcpy(s, buffer);
+    std::vector<char> buffer(n);
+    int result = _vsnprintf(_out_buffer, buffer.data(), format, &ctx->va_list);
+    std::strcpy(s, buffer.data());
     return result;
 }
 

src/core/libraries/network/net.cpp

@@ -904,7 +904,7 @@ const char* freebsd_inet_ntop6(const unsigned char* src, char* dst, u64 size) {
             tp += strlen(tp);
             break;
         }
-        tp += sprintf(tp, "%x", words[i]);
+        tp += snprintf(tp, sizeof(tmp) - (tp - tmp), "%x", words[i]);
     }
     /* Was it a trailing run of 0x00's? */
     if (best.base != -1 && (best.base + best.len) == (NS_IN6ADDRSZ / NS_INT16SZ))