[scudo] Use portable sysconf instead of deprecated getpagesize

[vitalybuka]

Does this work for SCUDO_FUCHSIA?

[ddcc]

It seems to be implemented, does that look right? https://cs.opensource.google/fuchsia/fuchsia/+/main:zircon/third_party/ulib/musl/src/conf/sysconf.c;l=56?q=sysconf&ss=fuchsia%2Ffuchsia

[vitalybuka]

LGTM

compiler-rt/lib/scudo/standalone/tests/map_test.cpp

 
 #include <string.h>
 #include <unistd.h>
 
 static const char *MappingName = "scudo:test";
 
 TEST(ScudoMapTest, PageSize) {
   EXPECT_EQ(scudo::getPageSizeCached(),
-            static_cast<scudo::uptr>(getpagesize()));
+            static_cast<scudo::uptr>(sysconf(_SC_PAGESIZE)));
 }
 
 TEST(ScudoMapDeathTest, MapNoAccessUnmap) {
   const scudo::uptr Size = 4 * scudo::getPageSizeCached();
   scudo::MapPlatformData Data = {};
   void *P = scudo::map(nullptr, Size, MappingName, MAP_NOACCESS, &Data);
   EXPECT_NE(P, nullptr);
   EXPECT_DEATH(memset(P, 0xaa, Size), "");