musl does not implement mallinfo()/mallinfo2()
(or rather, malloc-ng, musl's allocator, doesn't)

for some reason only outside of x86_64 HAVE_MALLINFO gets weirdly set by something
--
--- a/base/allocator/partition_allocator/src/partition_alloc/shim/allocator_shim_default_dispatch_to_partition_alloc.cc
+++ b/base/allocator/partition_allocator/src/partition_alloc/shim/allocator_shim_default_dispatch_to_partition_alloc.cc
@@ -646,7 +645,7 @@ SHIM_ALWAYS_EXPORT int mallopt(int cmd, int value) __THROW {
 
 #endif  // !PA_BUILDFLAG(IS_APPLE) && !PA_BUILDFLAG(IS_ANDROID)
 
-#if PA_BUILDFLAG(IS_LINUX) || PA_BUILDFLAG(IS_CHROMEOS)
+#if 0
 SHIM_ALWAYS_EXPORT struct mallinfo mallinfo(void) __THROW {
   partition_alloc::SimplePartitionStatsDumper allocator_dumper;
   Allocator()->DumpStats("malloc", true, &allocator_dumper);
--- a/base/process/process_metrics_posix.cc
+++ b/base/process/process_metrics_posix.cc
@@ -106,7 +107,8 @@ void IncreaseFdLimitTo(unsigned int max_descriptors) {
 
 #endif  // !BUILDFLAG(IS_FUCHSIA)
 
-#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS) || BUILDFLAG(IS_ANDROID)
+#if (BUILDFLAG(IS_LINUX) && defined(__GLIBC__)) || BUILDFLAG(IS_CHROMEOS) || \
+    BUILDFLAG(IS_ANDROID)
 namespace {
 
 size_t GetMallocUsageMallinfo() {
@@ -132,7 +134,8 @@ size_t ProcessMetrics::GetMallocUsage() {
   malloc_statistics_t stats = {0};
   malloc_zone_statistics(nullptr, &stats);
   return stats.size_in_use;
-#elif BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS) || BUILDFLAG(IS_ANDROID)
+#elif (BUILDFLAG(IS_LINUX) && defined(__GLIBC__)) || BUILDFLAG(IS_CHROMEOS) || \
+    BUILDFLAG(IS_ANDROID)
   return GetMallocUsageMallinfo();
 #elif BUILDFLAG(IS_FUCHSIA)
   // TODO(fuchsia): Not currently exposed. https://crbug.com/735087.
diff --git a/base/trace_event/malloc_dump_provider.cc b/base/trace_event/malloc_dump_provider.cc
index e37fc69c00..394f5dfdbb 100644
--- a/base/trace_event/malloc_dump_provider.cc
+++ b/base/trace_event/malloc_dump_provider.cc
@@ -189,7 +188,6 @@ void ReportMallinfoStats(ProcessMemoryDump* pmd,
 #define MALLINFO2_FOUND_IN_LIBC
   struct mallinfo2 info = mallinfo2();
 #endif
-#endif  // defined(__GLIBC__) && defined(__GLIBC_PREREQ)
 #if !defined(MALLINFO2_FOUND_IN_LIBC)
   struct mallinfo info = mallinfo();
 #endif
@@ -211,6 +209,7 @@ void ReportMallinfoStats(ProcessMemoryDump* pmd,
                               MemoryAllocatorDump::kUnitsBytes,
                               total_allocated_size);
   }
+#endif  // defined(__GLIBC__) && defined(__GLIBC_PREREQ)
 }
 #endif
 
@@ -368,7 +367,7 @@ bool MallocDumpProvider::OnMemoryDump(const MemoryDumpArgs& args,
                      &allocated_objects_count);
 #elif BUILDFLAG(IS_FUCHSIA)
 // TODO(fuchsia): Port, see https://crbug.com/706592.
-#else
+#elif defined(__GLIBC__)
   ReportMallinfoStats(/*pmd=*/nullptr, &total_virtual_size, &resident_size,
                       &allocated_objects_size, &allocated_objects_count);
 #endif
--- a/third_party/swiftshader/third_party/llvm-subzero/build/Linux/include/llvm/Config/config.h
+++ b/third_party/swiftshader/third_party/llvm-subzero/build/Linux/include/llvm/Config/config.h
@@ -133,7 +133,6 @@
 /* #undef HAVE_MALLCTL */
 
 /* Define to 1 if you have the `mallinfo' function. */
-#define HAVE_MALLINFO 1
 
 /* Some projects using SwiftShader bypass cmake (eg Chromium via gn) */
 /* so we need to check glibc version for the new API to be safe */
--- a/third_party/swiftshader/third_party/llvm-10.0/llvm/lib/Support/Unix/Process.inc
+++ b/third_party/swiftshader/third_party/llvm-10.0/llvm/lib/Support/Unix/Process.inc
@@ -83,11 +83,11 @@ Expected<unsigned> Process::getPageSize() {
 }
 
 size_t Process::GetMallocUsage() {
-#if defined(HAVE_MALLINFO2)
+#if 0
   struct mallinfo2 mi;
   mi = ::mallinfo2();
   return mi.uordblks;
-#elif defined(HAVE_MALLINFO)
+#elif 0
   struct mallinfo mi;
   mi = ::mallinfo();
   return mi.uordblks;
