Fix OSX build issues. Bump minimum required OSX version to 10.4

Only set MACOSX_DEPLOYMENT_TARGET to 10.4 if not set.
Always force -fno-stack-protector.

doc/install.html

@@ -104,7 +104,7 @@ operating systems, CPUs and compilers:
 <td class="compatcpu">CPU / OS</td>
 <td class="compatos"><a href="#posix">Linux</a> or<br><a href="#android">Android</a></td>
 <td class="compatos"><a href="#posix">*BSD, Other</a></td>
-<td class="compatos"><a href="#posix">OSX 10.3+</a> or<br><a href="#ios">iOS 3.0+</a></td>
+<td class="compatos"><a href="#posix">OSX 10.4+</a> or<br><a href="#ios">iOS 3.0+</a></td>
 <td class="compatos"><a href="#windows">Windows<br>XP/Vista/7</a></td>
 </tr>
 <tr class="odd separate">
@@ -210,8 +210,8 @@ You can add an extra prefix to the search paths by appending the
 make PREFIX=/home/myself/lj2
 </pre>
 <p>
-Note for OSX: <tt>MACOSX_DEPLOYMENT_TARGET</tt> is set to <tt>10.4</tt>
-in <tt>src/Makefile</tt>. Change it, if you want to build on an older version.
+Note for OSX: if the <tt>MACOSX_DEPLOYMENT_TARGET</tt> environment
+variable is not set, then it's forced to <tt>10.4</tt>.
 </p>
 <h3>Installing LuaJIT</h3>
 <p>

src/Makefile

@@ -219,10 +219,6 @@ TARGET_ALDFLAGS= $(LDOPTIONS) $(TARGET_XLDFLAGS) $(TARGET_FLAGS) $(TARGET_LDFLAG
 TARGET_ASHLDFLAGS= $(LDOPTIONS) $(TARGET_XSHLDFLAGS) $(TARGET_FLAGS) $(TARGET_SHLDFLAGS)
 TARGET_ALIBS= $(TARGET_XLIBS) $(LIBS) $(TARGET_LIBS)
 
-ifneq (,$(findstring stack-protector,$(shell $(TARGET_CC) -dumpspecs)))
-  TARGET_XCFLAGS+= -fno-stack-protector
-endif
-
 TARGET_TESTARCH=$(shell $(TARGET_CC) $(TARGET_TCFLAGS) -E lj_arch.h -dM)
 ifneq (,$(findstring LJ_TARGET_X64 ,$(TARGET_TESTARCH)))
   TARGET_CCARCH= x64
@@ -293,9 +289,12 @@ ifeq (Windows,$(TARGET_SYS))
   TARGET_DYNXLDOPTS=
 else
 ifeq (Darwin,$(TARGET_SYS))
-  export MACOSX_DEPLOYMENT_TARGET=10.4
+  ifeq (,$(MACOSX_DEPLOYMENT_TARGET))
+    export MACOSX_DEPLOYMENT_TARGET=10.4
+  endif
   TARGET_STRIP+= -x
   TARGET_AR+= 2>/dev/null
+  TARGET_XCFLAGS+= -fno-stack-protector
   TARGET_XSHLDFLAGS= -dynamiclib -single_module -undefined dynamic_lookup -fPIC
   TARGET_DYNXLDOPTS=
   TARGET_XSHLDFLAGS+= -install_name $(TARGET_DYLIBPATH) -compatibility_version $(MAJVER).$(MINVER) -current_version $(MAJVER).$(MINVER).$(RELVER)
@@ -307,10 +306,14 @@ else
 ifeq (iOS,$(TARGET_SYS))
   TARGET_STRIP+= -x
   TARGET_AR+= 2>/dev/null
+  TARGET_XCFLAGS+= -fno-stack-protector
   TARGET_XSHLDFLAGS= -dynamiclib -single_module -undefined dynamic_lookup -fPIC
   TARGET_DYNXLDOPTS=
   TARGET_XSHLDFLAGS+= -install_name $(TARGET_DYLIBPATH) -compatibility_version $(MAJVER).$(MINVER) -current_version $(MAJVER).$(MINVER).$(RELVER)
 else
+  ifneq (,$(findstring stack-protector,$(shell $(TARGET_CC) -dumpspecs)))
+    TARGET_XCFLAGS+= -fno-stack-protector
+  endif
   ifneq (SunOS,$(TARGET_SYS))
     TARGET_XLDFLAGS+= -Wl,-E
   endif