Merge branch 'master' into v2.1

diff --cc src/lib_os.c
Simple merge

diff --cc src/lj_arch.h
index b72dbccae43692b2c89704269de1e5208dc4441b,f1a1160fdfc221cee56d7710321828a16b253b43..c66a11c807e9884d13d2ea759e1bccc77fa1721b
--- 1/src/lj_arch.h
--- 2/src/lj_arch.h
+++ b/src/lj_arch.h
@@@ -491,13 -419,16 +491,16 @@@
  #define LJ_TARGET_UNALIGNED   0
  #endif
  
 -/* Various workarounds for embedded operating systems. */
 -#if (defined(__ANDROID__) && !defined(LJ_TARGET_X86ORX64)) || defined(__symbian__) || LJ_TARGET_XBOX360
 +/* Various workarounds for embedded operating systems or weak C runtimes. */
 +#if (defined(__ANDROID__) && !defined(LJ_TARGET_X86ORX64)) || defined(__symbian__) || LJ_TARGET_XBOX360 || LJ_TARGET_WINDOWS
  #define LUAJIT_NO_LOG2
  #endif
 -#if defined(__symbian__)
 +#if defined(__symbian__) || LJ_TARGET_WINDOWS
  #define LUAJIT_NO_EXP2
  #endif
+ #if LJ_TARGET_CONSOLE || (LJ_TARGET_IOS && __IPHONE_OS_VERSION_MIN_REQUIRED >= __IPHONE_8_0)
+ #define LJ_NO_SYSTEM          1
+ #endif
  
  #if defined(LUAJIT_NO_UNWIND) || defined(__symbian__) || LJ_TARGET_IOS || LJ_TARGET_PS3 || LJ_TARGET_PS4
  #define LJ_NO_UNWIND          1