Index: gcc/doc/invoke.texi
===================================================================
--- gcc/doc/invoke.texi	(revision 177846)
+++ gcc/doc/invoke.texi	(working copy)
@@ -5937,6 +5937,11 @@
 @file{../lib32}, or if OS libraries are present in @file{lib/@var{subdir}}
 subdirectories it prints e.g.@: @file{amd64}, @file{sparcv9} or @file{ev6}.
 
+@item -print-multiarch
+@opindex print-multiarch
+Print the path to OS libraries for the selected multiarch,
+relative to some @file{lib} subdirectory.
+
 @item -print-prog-name=@var{program}
 @opindex print-prog-name
 Like @option{-print-file-name}, but searches for a program such as @samp{cpp}.
Index: gcc/incpath.c
===================================================================
--- gcc/incpath.c	(revision 177846)
+++ gcc/incpath.c	(working copy)
@@ -150,8 +150,14 @@
 	      if (!filename_ncmp (p->fname, cpp_GCC_INCLUDE_DIR, len))
 		{
 		  char *str = concat (iprefix, p->fname + len, NULL);
-		  if (p->multilib && imultilib)
+		  if (p->multilib == 1 && imultilib)
 		    str = concat (str, dir_separator_str, imultilib, NULL);
+		  else if (p->multilib == 2)
+		    {
+		      if (!imultiarch)
+			continue;
+		      str = concat (str, dir_separator_str, imultiarch, NULL);
+		    }
 		  add_path (str, SYSTEM, p->cxx_aware, false);
 		}
 	    }
@@ -195,8 +201,14 @@
 	  else
 	    str = update_path (p->fname, p->component);
 
-	  if (p->multilib && imultilib)
+	  if (p->multilib == 1 && imultilib)
 	    str = concat (str, dir_separator_str, imultilib, NULL);
+	  else if (p->multilib == 2)
+	    {
+	      if (!imultiarch)
+		continue;
+	      str = concat (str, dir_separator_str, imultiarch, NULL);
+	    }
 
 	  add_path (str, SYSTEM, p->cxx_aware, false);
 	}
Index: gcc/gcc.c
===================================================================
--- gcc/gcc.c	(revision 177846)
+++ gcc/gcc.c	(working copy)
@@ -1147,6 +1147,11 @@
    set_multilib_dir based on the compilation options.  */
 
 static const char *multilib_os_dir;
+
+/* Subdirectory to use for locating libraries in multiarch conventions.  Set by
+   set_multilib_dir based on the compilation options.  */
+
+static const char *multiarch_dir;
 
 /* Structure to keep track of the specs that have been defined so far.
    These are accessed using %(specname) in a compiler or link
@@ -2072,6 +2077,7 @@
   struct prefix_list *pl;
   const char *multi_dir = NULL;
   const char *multi_os_dir = NULL;
+  const char *multiarch_suffix = NULL;
   const char *multi_suffix;
   const char *just_multi_suffix;
   char *path = NULL;
@@ -2089,11 +2095,14 @@
     }
   if (do_multi && multilib_os_dir && strcmp (multilib_os_dir, ".") != 0)
     multi_os_dir = concat (multilib_os_dir, dir_separator_str, NULL);
+  if (multiarch_dir)
+    multiarch_suffix = concat (multiarch_dir, dir_separator_str, NULL);
 
   while (1)
     {
       size_t multi_dir_len = 0;
       size_t multi_os_dir_len = 0;
+      size_t multiarch_len = 0;
       size_t suffix_len;
       size_t just_suffix_len;
       size_t len;
@@ -2102,6 +2111,8 @@
 	multi_dir_len = strlen (multi_dir);
       if (multi_os_dir)
 	multi_os_dir_len = strlen (multi_os_dir);
+      if (multiarch_suffix)
+	multiarch_len = strlen (multiarch_suffix);
       suffix_len = strlen (multi_suffix);
       just_suffix_len = strlen (just_multi_suffix);
 
@@ -2140,6 +2151,16 @@
 		break;
 	    }
 
+	  /* Now try the multiarch path.  */
+	  if (!skip_multi_dir
+	      && !pl->require_machine_suffix && multiarch_dir)
+	    {
+	      memcpy (path + len, multiarch_suffix, multiarch_len + 1);
+	      ret = callback (path, callback_info);
+	      if (ret)
+		break;
+	    }
+
 	  /* Now try the base path.  */
 	  if (!pl->require_machine_suffix
 	      && !(pl->os_multilib ? skip_multi_os_dir : skip_multi_dir))
@@ -3238,6 +3259,7 @@
     case OPT_print_multi_directory:
     case OPT_print_sysroot:
     case OPT_print_multi_os_directory:
+    case OPT_print_multiarch:
     case OPT_print_sysroot_headers_suffix:
     case OPT_time:
     case OPT_wrapper:
@@ -4891,6 +4913,15 @@
 		  do_spec_1 (" ", 0, NULL);
 		}
 
+	      if (multiarch_dir)
+		{
+		  do_spec_1 ("-imultiarch", 1, NULL);
+		  /* Make this a separate argument.  */
+		  do_spec_1 (" ", 0, NULL);
+		  do_spec_1 (multiarch_dir, 1, NULL);
+		  do_spec_1 (" ", 0, NULL);
+		}
+
 	      if (gcc_exec_prefix)
 		{
 		  do_spec_1 ("-iprefix", 1, NULL);
@@ -6508,6 +6539,15 @@
       return (0);
     }
 
+  if (print_multiarch)
+    {
+      if (multiarch_dir == NULL)
+	printf ("\n");
+      else
+	printf ("%s\n", multiarch_dir);
+      return (0);
+    }
+
   if (print_sysroot)
     {
       if (target_system_root)
@@ -7483,10 +7523,26 @@
 	    q++;
 	  if (q < end)
 	    {
-	      char *new_multilib_os_dir = XNEWVEC (char, end - q);
+	      const char *q2 = q + 1;
+	      char *new_multilib_os_dir;
+
+	      while (q2 < end && *q2 != ':')
+		q2++;
+	      if (*q2 == ':')
+		end = q2;
+	      new_multilib_os_dir = XNEWVEC (char, end - q);
 	      memcpy (new_multilib_os_dir, q + 1, end - q - 1);
 	      new_multilib_os_dir[end - q - 1] = '\0';
 	      multilib_os_dir = new_multilib_os_dir;
+
+	      end = this_path + this_path_len;
+	      if (q2 < end && *q2 == ':')
+		{
+		  char *new_multiarch_dir = XNEWVEC (char, end - q2);
+		  memcpy (new_multiarch_dir, q2 + 1, end - q2 - 1);
+		  new_multiarch_dir[end - q2 - 1] = '\0';
+		  multiarch_dir = new_multiarch_dir;
+		}
 	      break;
 	    }
 	}
@@ -7548,7 +7604,7 @@
       /* When --disable-multilib was used but target defines
 	 MULTILIB_OSDIRNAMES, entries starting with .: are there just
 	 to find multilib_os_dir, so skip them from output.  */
-      if (this_path[0] == '.' && this_path[1] == ':')
+      if (this_path[0] == '.' && this_path[1] == ':' && this_path[2] != ':')
 	skip = 1;
 
       /* Check for matches with the multilib_exclusions. We don't bother
Index: gcc/genmultilib
===================================================================
--- gcc/genmultilib	(revision 177846)
+++ gcc/genmultilib	(working copy)
@@ -73,6 +73,8 @@
 # the os directory names are used exclusively.  Use the mapping when
 # there is no one-to-one equivalence between GCC levels and the OS.
 
+# The optional eight argument is the multiarch name.
+
 # The last option should be "yes" if multilibs are enabled.  If it is not
 # "yes", all GCC multilib dir names will be ".".
 
@@ -121,7 +123,8 @@
 extra=$5
 exclusions=$6
 osdirnames=$7
-enable_multilib=$8
+multiarch=$8
+enable_multilib=$9
 
 echo "static const char *const multilib_raw[] = {"
 
@@ -222,6 +225,9 @@
 # names.
 toosdirnames=
 defaultosdirname=
+if [ -n "${multiarch}" ]; then
+  defaultosdirname=::${multiarch}
+fi
 if [ -n "${osdirnames}" ]; then
   set x ${osdirnames}
   shift
@@ -229,6 +235,9 @@
     case "$1" in
       .=*)
         defaultosdirname=`echo $1 | sed 's|^.=|:|'`
+	if [ -n "${multiarch}" ]; then
+	  defaultosdirname=${defaultosdirname}:${multiarch}
+	fi
 	shift
 	;;
       *=*)
@@ -314,13 +323,13 @@
     dirout=`echo ${combo} | sed -e 's/=/-/g'`
   fi
   # Remove the leading and trailing slashes.
-  dirout=`echo ${dirout} | sed -e 's|^/||' -e 's|/$||g'`
+  dirout=`echo ${dirout} | sed -e 's|^/||' -e 's|/*:/*|:|' -e 's|/$||g'`
 
   # Use the OS directory names rather than the option names.
   if [ -n "${toosdirnames}" ]; then
     osdirout=`echo ${combo} | sed ${toosdirnames}`
     # Remove the leading and trailing slashes.
-    osdirout=`echo ${osdirout} | sed -e 's|^/||' -e 's|/$||g'`
+    osdirout=`echo ${osdirout} | sed -e 's|^/||' -e 's|/*:/*|:|' -e 's|/$||g'`
     if [ "x${enable_multilib}" != xyes ]; then
       dirout=".:${osdirout}"
       disable_multilib=yes
Index: gcc/cppdefault.c
===================================================================
--- gcc/cppdefault.c	(revision 177846)
+++ gcc/cppdefault.c	(working copy)
@@ -64,6 +64,7 @@
 #endif
 #ifdef LOCAL_INCLUDE_DIR
     /* /usr/local/include comes before the fixincluded header files.  */
+    { LOCAL_INCLUDE_DIR, 0, 0, 1, 1, 2 },
     { LOCAL_INCLUDE_DIR, 0, 0, 1, 1, 0 },
 #endif
 #ifdef PREFIX_INCLUDE_DIR
@@ -95,6 +96,7 @@
 #endif
 #ifdef STANDARD_INCLUDE_DIR
     /* /usr/include comes dead last.  */
+    { STANDARD_INCLUDE_DIR, STANDARD_INCLUDE_COMPONENT, 0, 0, 1, 2 },
     { STANDARD_INCLUDE_DIR, STANDARD_INCLUDE_COMPONENT, 0, 0, 1, 0 },
 #endif
     { 0, 0, 0, 0, 0, 0 }
Index: gcc/cppdefault.h
===================================================================
--- gcc/cppdefault.h	(revision 177846)
+++ gcc/cppdefault.h	(working copy)
@@ -43,9 +43,11 @@
 				   C++.  */
   const char add_sysroot;	/* FNAME should be prefixed by
 				   cpp_SYSROOT.  */
-  const char multilib;		/* FNAME should have the multilib path
-				   specified with -imultilib
-				   appended.  */
+  const char multilib;		/* FNAME should have appended
+				   - the multilib path specified with -imultilib
+				     when 1 is passed,
+				   - the multiarch path specified with
+				     -imultiarch, when 2 is passed.  */
 };
 
 extern const struct default_include cpp_include_defaults[];
Index: gcc/common.opt
===================================================================
--- gcc/common.opt	(revision 177846)
+++ gcc/common.opt	(working copy)
@@ -345,6 +345,9 @@
 -print-multi-os-directory
 Driver Alias(print-multi-os-directory)
 
+-print-multiarch
+Driver Alias(print-multiarch)
+
 -print-prog-name
 Driver Separate Alias(print-prog-name=)
 
@@ -2231,6 +2234,10 @@
 Common Joined Var(plugindir_string) Init(0)
 -iplugindir=<dir>	Set <dir> to be the default plugin directory
 
+imultiarch
+Common Joined Separate RejectDriver Var(imultiarch) Init(0)
+-imultiarch <dir>	Set <dir> to be the multiarch include subdirectory
+
 l
 Driver Joined Separate
 
@@ -2288,6 +2295,9 @@
 
 print-multi-os-directory
 Driver Var(print_multi_os_directory)
+ 
+print-multiarch
+Driver Var(print_multiarch)
 
 print-prog-name=
 Driver JoinedOrMissing Var(print_prog_name)
Index: gcc/config.gcc
===================================================================
--- gcc/config.gcc	(revision 177846)
+++ gcc/config.gcc	(working copy)
@@ -1315,12 +1315,14 @@
 		;;
 	i[34567]86-*-kfreebsd*-gnu)
 		tm_file="${tm_file} i386/gnu-user.h kfreebsd-gnu.h i386/kfreebsd-gnu.h"
+		tmake_file="${tmake_file} i386/t-kfreebsd"
 		;;
 	i[34567]86-*-kopensolaris*-gnu)
 		tm_file="${tm_file} i386/gnu-user.h kopensolaris-gnu.h i386/kopensolaris-gnu.h"
 		;;
 	i[34567]86-*-gnu*)
 		tm_file="$tm_file i386/gnu-user.h gnu.h i386/gnu.h"
+		tmake_file="${tmake_file} i386/t-gnu"
 		;;
 	esac
 	tmake_file="${tmake_file} i386/t-crtstuff"
Index: gcc/Makefile.in
===================================================================
--- gcc/Makefile.in	(revision 177846)
+++ gcc/Makefile.in	(working copy)
@@ -1935,10 +1935,11 @@
 	    "$(MULTILIB_EXTRA_OPTS)" \
 	    "$(MULTILIB_EXCLUSIONS)" \
 	    "$(MULTILIB_OSDIRNAMES)" \
+	    "$(MULTIARCH_DIRNAME)" \
 	    "@enable_multilib@" \
 	    > tmp-mlib.h; \
 	else \
-	  $(SHELL) $(srcdir)/genmultilib '' '' '' '' '' '' '' no \
+	  $(SHELL) $(srcdir)/genmultilib '' '' '' '' '' '' '' "$(MULTIARCH_DIRNAME)" no \
 	    > tmp-mlib.h; \
 	fi
 	$(SHELL) $(srcdir)/../move-if-change tmp-mlib.h multilib.h
Index: gcc/config/alpha/t-linux
===================================================================
--- gcc/config/alpha/t-linux	(revision 177846)
+++ gcc/config/alpha/t-linux	(working copy)
@@ -1 +1,3 @@
 SHLIB_MAPFILES += $(srcdir)/config/alpha/libgcc-alpha-ldbl.ver
+
+MULTIARCH_DIRNAME = alpha-linux-gnu
Index: gcc/config/s390/t-linux64
===================================================================
--- gcc/config/s390/t-linux64	(revision 177846)
+++ gcc/config/s390/t-linux64	(working copy)
@@ -7,4 +7,4 @@
 
 MULTILIB_OPTIONS = m64/m31
 MULTILIB_DIRNAMES = 64 32
-MULTILIB_OSDIRNAMES = ../lib64 $(if $(wildcard $(shell echo $(SYSTEM_HEADER_DIR))/../../usr/lib32),../lib32,../lib)
+MULTILIB_OSDIRNAMES = ../lib64:s390x-linux-gnu $(if $(wildcard $(shell echo $(SYSTEM_HEADER_DIR))/../../usr/lib32),../lib32,../lib):s390-linux-gnu
Index: gcc/config/sparc/t-linux64
===================================================================
--- gcc/config/sparc/t-linux64	(revision 177846)
+++ gcc/config/sparc/t-linux64	(working copy)
@@ -26,7 +26,7 @@
 
 MULTILIB_OPTIONS = m64/m32
 MULTILIB_DIRNAMES = 64 32
-MULTILIB_OSDIRNAMES = ../lib64 $(if $(wildcard $(shell echo $(SYSTEM_HEADER_DIR))/../../usr/lib32),../lib32,../lib)
+MULTILIB_OSDIRNAMES = ../lib64:sparc64-linux-gnu $(if $(wildcard $(shell echo $(SYSTEM_HEADER_DIR))/../../usr/lib32),../lib32,../lib):sparc-linux-gnu
 
 LIBGCC = stmp-multilib
 INSTALL_LIBGCC = install-multilib
Index: gcc/config/sparc/t-linux
===================================================================
--- gcc/config/sparc/t-linux	(revision 177846)
+++ gcc/config/sparc/t-linux	(working copy)
@@ -3,3 +3,5 @@
 # Avoid the t-linux version file.
 SHLIB_MAPFILES = $$(libgcc_objdir)/libgcc-std.ver \
 		 $(srcdir)/config/sparc/libgcc-sparc-glibc.ver
+
+MULTIARCH_DIRNAME = sparc-linux-gnu
Index: gcc/config/i386/t-kfreebsd
===================================================================
--- gcc/config/i386/t-kfreebsd	(revision 0)
+++ gcc/config/i386/t-kfreebsd	(revision 0)
@@ -0,0 +1,5 @@
+MULTIARCH_DIRNAME = i386-kfreebsd-gnu
+
+# MULTILIB_OSDIRNAMES are set in t-linux64.
+KFREEBSD_OS = $(filter kfreebsd%, $(word 3, $(subst -, ,$(arch2))))
+MULTILIB_OSDIRNAMES := $(subst linux,$(KFREEBSD_OS),$(MULTILIB_OSDIRNAMES))
Index: gcc/config/i386/t-gnu
===================================================================
--- gcc/config/i386/t-gnu	(revision 0)
+++ gcc/config/i386/t-gnu	(revision 0)
@@ -0,0 +1 @@
+MULTIARCH_DIRNAME = i386-gnu
Index: gcc/config/i386/t-linux
===================================================================
--- gcc/config/i386/t-linux	(revision 177846)
+++ gcc/config/i386/t-linux	(working copy)
@@ -3,3 +3,5 @@
 # t-slibgcc-elf-ver and t-linux
 SHLIB_MAPFILES = $$(libgcc_objdir)/libgcc-std.ver \
 		 $(srcdir)/config/i386/libgcc-glibc.ver
+
+MULTIARCH_DIRNAME = i386-linux-gnu
Index: gcc/config/i386/t-linux64
===================================================================
--- gcc/config/i386/t-linux64	(revision 177846)
+++ gcc/config/i386/t-linux64	(working copy)
@@ -34,8 +34,8 @@
 comma=,
 MULTILIB_OPTIONS    = $(subst $(comma),/,$(TM_MULTILIB_CONFIG))
 MULTILIB_DIRNAMES   = $(patsubst m%, %, $(subst /, ,$(MULTILIB_OPTIONS)))
-MULTILIB_OSDIRNAMES = m64=../lib64
-MULTILIB_OSDIRNAMES+= m32=$(if $(wildcard $(shell echo $(SYSTEM_HEADER_DIR))/../../usr/lib32),../lib32,../lib)
+MULTILIB_OSDIRNAMES = m64=../lib64:x86_64-linux-gnu
+MULTILIB_OSDIRNAMES+= m32=$(if $(wildcard $(shell echo $(SYSTEM_HEADER_DIR))/../../usr/lib32),../lib32,../lib):i386-linux-gnu
 MULTILIB_OSDIRNAMES+= mx32=../libx32
 
 LIBGCC = stmp-multilib
Index: gcc/config/ia64/t-glibc
===================================================================
--- gcc/config/ia64/t-glibc	(revision 177846)
+++ gcc/config/ia64/t-glibc	(working copy)
@@ -1 +1,5 @@
 SHLIB_MAPFILES += $(srcdir)/config/ia64/libgcc-glibc.ver
+
+ifneq (,$(findstring linux, $(target)))
+MULTIARCH_DIRNAME = ia64-linux-gnu
+endif
Index: gcc/config/m68k/t-linux
===================================================================
--- gcc/config/m68k/t-linux	(revision 177846)
+++ gcc/config/m68k/t-linux	(working copy)
@@ -21,6 +21,8 @@
 # Only include multilibs for 680x0 CPUs with an MMU.
 M68K_MLIB_CPU += && (CPU ~ "^m680") && (FLAGS ~ "FL_MMU")
 
+MULTIARCH_DIRNAME = m68k-linux-gnu
+
 # This rule uses MULTILIB_MATCHES to generate a definition of
 # SYSROOT_SUFFIX_SPEC.
 sysroot-suffix.h: $(srcdir)/config/m68k/print-sysroot-suffix.sh
Index: gcc/config/rs6000/t-linux64
===================================================================
--- gcc/config/rs6000/t-linux64	(revision 177846)
+++ gcc/config/rs6000/t-linux64	(working copy)
@@ -33,5 +33,5 @@
 MULTILIB_EXTRA_OPTS     = fPIC mstrict-align
 MULTILIB_EXCEPTIONS     = m64/msoft-float
 MULTILIB_EXCLUSIONS     = m64/!m32/msoft-float
-MULTILIB_OSDIRNAMES	= ../lib64 $(if $(wildcard $(shell echo $(SYSTEM_HEADER_DIR))/../../usr/lib32),../lib32,../lib) nof
+MULTILIB_OSDIRNAMES	= ../lib64:powerpc64-linux-gnu $(if $(wildcard $(shell echo $(SYSTEM_HEADER_DIR))/../../usr/lib32),../lib32,../lib):powerpc-linux-gnu nof
 MULTILIB_MATCHES        = $(MULTILIB_MATCHES_FLOAT)
Index: gcc/config/pa/t-linux
===================================================================
--- gcc/config/pa/t-linux	(revision 177846)
+++ gcc/config/pa/t-linux	(working copy)
@@ -35,3 +35,5 @@
 
 # Compile crtbeginS.o and crtendS.o as PIC.
 CRTSTUFF_T_CFLAGS_S = -fPIC
+
+MULTIARCH_DIRNAME = hppa-linux-gnu
Index: gcc/config/mips/t-linux64
===================================================================
--- gcc/config/mips/t-linux64	(revision 177846)
+++ gcc/config/mips/t-linux64	(working copy)
@@ -22,6 +22,10 @@
 else
 MULTILIB_DIRNAMES = n32 32 64
 endif
-MULTILIB_OSDIRNAMES = ../lib32 ../lib ../lib64
+MIPS_EL = $(if $(filter %el, $(firstword $(subst -, ,$(arch)))),el)
+MULTILIB_OSDIRNAMES = \
+	../lib32:mips64$(MIPS_EL)-linux-gnuabin32 \
+	../lib:mips$(MIPS_EL)-linux-gnu \
+	../lib64:mips64$(MIPS_EL)-linux-gnuabi64
 
 EXTRA_MULTILIB_PARTS=crtbegin.o crtend.o crtbeginS.o crtendS.o crtbeginT.o
