diff --git a/gcc/config/darwin-driver.c b/gcc/config/darwin-driver.c
index 727ea53..4042a68 100644
--- a/gcc/config/darwin-driver.c
+++ b/gcc/config/darwin-driver.c
@@ -96,73 +96,36 @@ darwin_find_version_from_kernel (void)
    included in tm.h).  This may be overidden by setting the flag explicitly
    (or by the MACOSX_DEPLOYMENT_TARGET environment).  */
 
-static void
-darwin_default_min_version (unsigned int *decoded_options_count,
-			    struct cl_decoded_option **decoded_options)
+static const char *
+darwin_default_min_version (void)
 {
-  const unsigned int argc = *decoded_options_count;
-  struct cl_decoded_option *const argv = *decoded_options;
-  unsigned int i;
-  const char *new_flag;
-
-  /* If the command-line is empty, just return.  */
-  if (argc <= 1)
-    return;
-  
-  /* Don't do this if the user specified -mmacosx-version-min= or
-     -mno-macosx-version-min.  */
-  for (i = 1; i < argc; i++)
-    if (argv[i].opt_index == OPT_mmacosx_version_min_)
-      return;
-
-  /* Retrieve the deployment target from the environment and insert
-     it as a flag.  */
-  {
-    const char * macosx_deployment_target;
-    macosx_deployment_target = getenv ("MACOSX_DEPLOYMENT_TARGET");
-    if (macosx_deployment_target
-	/* Apparently, an empty string for MACOSX_DEPLOYMENT_TARGET means
-	   "use the default".  Or, possibly "use 10.1".  We choose
-	   to ignore the environment variable, as if it was never set.  */
-	&& macosx_deployment_target[0])
-      {
-	++*decoded_options_count;
-	*decoded_options = XNEWVEC (struct cl_decoded_option,
-				    *decoded_options_count);
-	(*decoded_options)[0] = argv[0];
-	generate_option (OPT_mmacosx_version_min_, macosx_deployment_target,
-			 1, CL_DRIVER, &(*decoded_options)[1]);
-	memcpy (*decoded_options + 2, argv + 1,
-		(argc - 1) * sizeof (struct cl_decoded_option));
-	return;
-      }
-  }
+  /* Try to retrieve the deployment target from the environment.  */
+  const char *new_flag = getenv ("MACOSX_DEPLOYMENT_TARGET");
 
+  /* Apparently, an empty string for MACOSX_DEPLOYMENT_TARGET means
+     "use the default".  Or, possibly "use 10.1".  We choose
+     to ignore the environment variable, as if it was never set.  */
+  if (new_flag == NULL || new_flag[0] == 0)
 #ifndef CROSS_DIRECTORY_STRUCTURE
-
-  /* Try to find the version from the kernel, if we fail - we print a message 
-     and give up.  */
-  new_flag = darwin_find_version_from_kernel ();
-  if (!new_flag)
-    return;
-
+    /* Try to find the version from the kernel, if we fail - we print a
+       message and give up.  */
+    new_flag = darwin_find_version_from_kernel ();
 #else
-
-  /* For cross-compilers, default to the target OS version. */
-  new_flag = DEF_MIN_OSX_VERSION;
-
+    /* For cross-compilers, default to a minimum version determined by
+       the configuration. */
+    new_flag = DEF_MIN_OSX_VERSION;
 #endif /* CROSS_DIRECTORY_STRUCTURE */
 
-  /* Add the new flag.  */
-  ++*decoded_options_count;
-  *decoded_options = XNEWVEC (struct cl_decoded_option,
-			      *decoded_options_count);
-  (*decoded_options)[0] = argv[0];
-  generate_option (OPT_mmacosx_version_min_, new_flag,
-		   1, CL_DRIVER, &(*decoded_options)[1]);
-  memcpy (*decoded_options + 2, argv + 1,
-	  (argc - 1) * sizeof (struct cl_decoded_option));
-  return;
+  if (new_flag != NULL)
+    {
+      size_t len = strlen (new_flag);
+      if (len > 128) { /* Arbitrary limit, number should be like xx.yy.zz */
+	warning (0, "couldn%'t understand version %s\n", new_flag);
+	return NULL;
+      }
+      new_flag = strndup (new_flag, len);
+    }
+  return new_flag;
 }
 
 /* Translate -filelist and -framework options in *DECODED_OPTIONS
@@ -187,6 +150,8 @@ darwin_driver_init (unsigned int *decoded_options_count,
   bool seenM64 = false;
   bool appendM32 = false;
   bool appendM64 = false;
+  const char *vers_string = NULL;
+  bool seen_version_min = false;
 
   for (i = 1; i < *decoded_options_count; i++)
     {
@@ -246,12 +211,15 @@ darwin_driver_init (unsigned int *decoded_options_count,
 			   CL_DRIVER, &(*decoded_options)[i]);
 	  break;
 
+	case OPT_mmacosx_version_min_:
+	  seen_version_min = true;
+	  vers_string = strndup ((*decoded_options)[i].arg, 32);
+
 	default:
 	  break;
 	}
     }
 
-  darwin_default_min_version (decoded_options_count, decoded_options);
   /* Turn -arch xxxx into the appropriate -m32/-m64 flag.
      If the User tried to specify multiple arch flags (which is possible with
      some Darwin compilers) warn that this mode is not supported by this
@@ -308,4 +276,21 @@ darwin_driver_init (unsigned int *decoded_options_count,
 		       &(*decoded_options)[*decoded_options_count - 1]);
     }
 
+  /* We will need to know the OS X version we're trying to build for here
+     so that we can figure out the mechanism and source for the sysroot to
+     be used.  */
+  if (! seen_version_min && *decoded_options_count > 1)
+    {
+      /* Not set by the User, try to figure it out.  */
+      vers_string = darwin_default_min_version ();
+      if (vers_string != NULL)
+	{
+	  ++*decoded_options_count;
+	  *decoded_options = XRESIZEVEC (struct cl_decoded_option,
+					 *decoded_options,
+					 *decoded_options_count);
+	  generate_option (OPT_mmacosx_version_min_, vers_string, 1, CL_DRIVER,
+			  &(*decoded_options)[*decoded_options_count - 1]);
+	}
+    }
 }
diff --git a/gcc/config/darwin.c b/gcc/config/darwin.c
index b6effec..7f3c915 100644
--- a/gcc/config/darwin.c
+++ b/gcc/config/darwin.c
@@ -3064,6 +3064,14 @@ darwin_kextabi_p (void) {
 void
 darwin_override_options (void)
 {
+  /* If a compiler is called directly, rather than via the driver, but
+     without a target system version specified, warn the user that a
+     default is in use.  */
+  if (!global_options_set.x_darwin_macosx_version_min)
+    warning_at (UNKNOWN_LOCATION, 0,
+		"%<-mmacosx-version-min%> is not set; using %<%s%>",
+		darwin_macosx_version_min);
+
   /* Keep track of which (major) version we're generating code for.  */
   if (darwin_macosx_version_min)
     {
diff --git a/gcc/config/darwin.h b/gcc/config/darwin.h
index 9a31952..bb4451a 100644
--- a/gcc/config/darwin.h
+++ b/gcc/config/darwin.h
@@ -271,7 +271,6 @@ extern GTY(()) int darwin_ms_struct;
    %{headerpad_max_install_names} \
    %{Zimage_base*:-image_base %*} \
    %{Zinit*:-init %*} \
-   %{!mmacosx-version-min=*:-macosx_version_min %(darwin_minversion)} \
    %{mmacosx-version-min=*:-macosx_version_min %*} \
    %{nomultidefs} \
    %{Zmulti_module:-multi_module} %{Zsingle_module:-single_module} \
@@ -370,8 +369,7 @@ extern GTY(()) int darwin_ms_struct;
 
 #define DARWIN_EXTRA_SPECS						\
   { "darwin_crt1", DARWIN_CRT1_SPEC },					\
-  { "darwin_dylib1", DARWIN_DYLIB1_SPEC },				\
-  { "darwin_minversion", DARWIN_MINVERSION_SPEC },
+  { "darwin_dylib1", DARWIN_DYLIB1_SPEC },
 
 #define DARWIN_DYLIB1_SPEC						\
   "%:version-compare(!> 10.5 mmacosx-version-min= -ldylib1.o)		\
@@ -916,7 +914,9 @@ extern void darwin_driver_init (unsigned int *,struct cl_decoded_option **);
 #define SUPPORTS_INIT_PRIORITY 0
 
 /* When building cross-compilers (and native crosses) we shall default to 
-   providing an osx-version-min of this unless overridden by the User.  */
-#define DEF_MIN_OSX_VERSION "10.4"
+   providing an osx-version-min of this unless overridden by the User.
+   10.5 is the only version that fully supports all our archs so that's the
+   fall-back default.  */
+#define DEF_MIN_OSX_VERSION "10.5"
 
 #endif /* CONFIG_DARWIN_H */
diff --git a/gcc/config/darwin.opt b/gcc/config/darwin.opt
index 5ab0e5c..eb1afe7 100644
--- a/gcc/config/darwin.opt
+++ b/gcc/config/darwin.opt
@@ -226,10 +226,9 @@ Generate code suitable for fast turn around debugging
 ; The Init here is for the convenience of GCC developers, so that cc1
 ; and cc1plus don't crash if no -mmacosx-version-min is passed.  The
 ; driver will always pass a -mmacosx-version-min, so in normal use the
-; Init is never used.  Useful for setting the OS on which people
-; usually debug.
+; Init is never used.
 mmacosx-version-min=
-Target Joined Report Var(darwin_macosx_version_min) Init("10.6")
+Target Joined Report Var(darwin_macosx_version_min) Init(DEF_MIN_OSX_VERSION)
 The earliest MacOS X version on which this program will run
 
 mone-byte-bool
diff --git a/gcc/config/darwin12.h b/gcc/config/darwin12.h
index fdc1d0d..506364a 100644
--- a/gcc/config/darwin12.h
+++ b/gcc/config/darwin12.h
@@ -25,3 +25,6 @@ along with GCC; see the file COPYING3.  If not see
       %:version-compare(>= 10.6 mmacosx-version-min= -lSystem) } } \
    %{fno-pic|fno-PIC|fno-pie|fno-PIE|fapple-kext|mkernel|static|mdynamic-no-pic: \
       %:version-compare(>= 10.7 mmacosx-version-min= -no_pie) } %G %L"
+
+#undef DEF_MIN_OSX_VERSION
+#define DEF_MIN_OSX_VERSION "10.8"
diff --git a/gcc/config/i386/darwin.h b/gcc/config/i386/darwin.h
index 6a2471a..2006a75 100644
--- a/gcc/config/i386/darwin.h
+++ b/gcc/config/i386/darwin.h
@@ -108,7 +108,6 @@ extern int darwin_emit_branch_islands;
 #undef CC1_SPEC
 #define CC1_SPEC "%(cc1_cpu) \
   %{!mkernel:%{!static:%{!mdynamic-no-pic:-fPIC}}} \
-  %{!mmacosx-version-min=*:-mmacosx-version-min=%(darwin_minversion)} \
   %{g: %{!fno-eliminate-unused-debug-symbols: -feliminate-unused-debug-symbols }} " \
   DARWIN_CC1_SPEC
 
@@ -119,15 +118,6 @@ extern int darwin_emit_branch_islands;
 #define DARWIN_ARCH_SPEC "%{m64:x86_64;:i386}"
 #define DARWIN_SUBARCH_SPEC DARWIN_ARCH_SPEC
 
-/* Determine a minimum version based on compiler options.  */
-#define DARWIN_MINVERSION_SPEC				\
- "%{!m64|fgnu-runtime:10.4;				\
-    ,objective-c|,objc-cpp-output:10.5;			\
-    ,objective-c-header:10.5;				\
-    ,objective-c++|,objective-c++-cpp-output:10.5;	\
-    ,objective-c++-header|,objc++-cpp-output:10.5;	\
-    :10.4}"
-
 #undef ENDFILE_SPEC
 #define ENDFILE_SPEC \
   "%{Ofast|ffast-math|funsafe-math-optimizations:crtfastmath.o%s} \
diff --git a/gcc/config/rs6000/darwin.h b/gcc/config/rs6000/darwin.h
index 14d5477..82fcad2 100644
--- a/gcc/config/rs6000/darwin.h
+++ b/gcc/config/rs6000/darwin.h
@@ -93,7 +93,6 @@ extern int darwin_emit_branch_islands;
   %(cc1_cpu) \
   %{g: %{!fno-eliminate-unused-debug-symbols: -feliminate-unused-debug-symbols }} \
   %{static: %{Zdynamic: %e conflicting code gen style switches are used}}\
-  %{!mmacosx-version-min=*:-mmacosx-version-min=%(darwin_minversion)} \
   %{!mkernel:%{!static:%{!mdynamic-no-pic:-fPIC}}} \
   %{faltivec:-maltivec -include altivec.h} %{fno-altivec:-mno-altivec} \
   %<faltivec %<fno-altivec " \
@@ -124,17 +123,6 @@ extern int darwin_emit_branch_islands;
 #define DARWIN_CRT2_SPEC \
   "%{!m64:%:version-compare(!> 10.4 mmacosx-version-min= crt2.o%s)}"
 
-/* Determine a minimum version based on compiler options.  */
-#define DARWIN_MINVERSION_SPEC					\
-  "%{m64:%{fgnu-runtime:10.4;					\
-	   ,objective-c|,objc-cpp-output:10.5;			\
-	   ,objective-c-header:10.5;				\
-	   ,objective-c++|,objective-c++-cpp-output:10.5;	\
-	   ,objective-c++-header|,objc++-cpp-output:10.5;	\
-	   :10.4};						\
-     shared-libgcc:10.3;					\
-     :10.1}"
-
 #undef SUBTARGET_EXTRA_SPECS
 #define SUBTARGET_EXTRA_SPECS			\
   DARWIN_EXTRA_SPECS                            \
