From a320f1a0822256e7219d6780fbc5ecbe956d3db0 Mon Sep 17 00:00:00 2001
From: Vyacheslav Egorov <me@mrale.ph>
Date: Tue, 20 Oct 2015 17:43:02 +0200
Subject: [PATCH] On Mac OS switch default compiler from gcc to clang. XCode
 has been shipping with clang since XCode 5.0 released in September 2013.

Change iOS cross compilation instructions to rely on `xcrun` to locate compiler instead of hard-coding the path and SDK version. Provide instructions for cross-compilation to ARM64.

Fixes issue #1. Fixes issue #4.
---
 doc/install.html | 19 ++++++++++++-------
 src/Makefile     | 48 ++++++++++++++++++++++++++++++------------------
 2 files changed, 42 insertions(+), 25 deletions(-)

diff --git a/doc/install.html b/doc/install.html
index b5df697b..42f864a4 100644
--- a/doc/install.html
+++ b/doc/install.html
@@ -453,13 +453,18 @@ much slower than the JIT compiler. Please complain to Apple, not me.
 Or use Android. :-p
 </p>
 <pre class="code">
-IXCODE=`xcode-select -print-path`
-ISDK=$IXCODE/Platforms/iPhoneOS.platform/Developer
-ISDKVER=iPhoneOS6.0.sdk
-ISDKP=$ISDK/usr/bin/
-ISDKF="-arch armv7 -isysroot $ISDK/SDKs/$ISDKVER"
-make HOST_CC="gcc -m32 -arch i386" CROSS=$ISDKP TARGET_FLAGS="$ISDKF" \
-     TARGET_SYS=iOS
+# Cross-compile for a 32bit ARM.
+ISDKP=`xcrun --sdk iphoneos --show-sdk-path`
+ICC=`xcrun --sdk iphoneos --find clang`
+ISDKF="-arch armv7 -isysroot $ISDKP"
+make HOST_CC="clang -m32 -arch i386" CROSS="$(dirname $ICC)/" \
+     TARGET_FLAGS="$ISDKF" TARGET_SYS=iOS
+
+# Cross-compile for an ARM64.
+ISDKP=`xcrun --sdk iphoneos --show-sdk-path`
+ICC=`xcrun --sdk iphoneos --find clang`
+ISDKF="-arch arm64 -isysroot $ISDKP"
+make CROSS="$(dirname $ICC)/" TARGET_FLAGS="$ISDKF" TARGET_SYS=iOS
 </pre>
 
 <h3 id="consoles">Cross-compiling for consoles</h3>
diff --git a/src/Makefile b/src/Makefile
index 532da6e9..c8d04fa5 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -16,6 +16,33 @@ RELVER=  0
 ABIVER=  5.1
 NODOTABIVER= 51
 
+##############################################################################
+################################  HOST SYSTEM  ###############################
+##############################################################################
+
+ifeq (Windows,$(findstring Windows,$(OS))$(MSYSTEM)$(TERM))
+  HOST_SYS= Windows
+  HOST_RM= del
+else
+  HOST_SYS:= $(shell uname -s)
+  ifneq (,$(findstring MINGW,$(HOST_SYS)))
+    HOST_SYS= Windows
+    HOST_MSYS= mingw
+  endif
+  ifneq (,$(findstring CYGWIN,$(HOST_SYS)))
+    HOST_SYS= Windows
+    HOST_MSYS= cygwin
+  endif
+endif
+
+# We default to GCC on all platforms except Mac OS where the default compiler is
+# clang starting with XCode 5.0.
+ifneq (Darwin,$(HOST_SYS))
+  DEFAULT_CC= gcc
+else
+  DEFAULT_CC= clang
+endif
+
 ##############################################################################
 #############################  COMPILER OPTIONS  #############################
 ##############################################################################
@@ -25,10 +52,10 @@ NODOTABIVER= 51
 # with "make clean", followed by "make" if you change any options.
 #
 # LuaJIT builds as a native 32 or 64 bit binary by default.
-CC= gcc
+CC= $(DEFAULT_CC)
 #
 # Use this if you want to force a 32 bit build on a 64 bit multilib OS.
-#CC= gcc -m32
+# CC= $(DEFAULT_CC) -m32
 #
 # Since the assembler part does NOT maintain a frame pointer, it's pointless
 # to slow down the C part by not omitting it. Debugging, tracebacks and
@@ -268,24 +295,9 @@ ifneq (,$(LMULTILIB))
 endif
 
 ##############################################################################
-# System detection.
+# Target system features.
 ##############################################################################
 
-ifeq (Windows,$(findstring Windows,$(OS))$(MSYSTEM)$(TERM))
-  HOST_SYS= Windows
-  HOST_RM= del
-else
-  HOST_SYS:= $(shell uname -s)
-  ifneq (,$(findstring MINGW,$(HOST_SYS)))
-    HOST_SYS= Windows
-    HOST_MSYS= mingw
-  endif
-  ifneq (,$(findstring CYGWIN,$(HOST_SYS)))
-    HOST_SYS= Windows
-    HOST_MSYS= cygwin
-  endif
-endif
-
 TARGET_SYS?= $(HOST_SYS)
 ifeq (Windows,$(TARGET_SYS))
   TARGET_STRIP+= --strip-unneeded