diff --git a/config.sub b/config.sub
index fab0aa3..b83660a 100755
--- a/config.sub
+++ b/config.sub
@@ -120,7 +120,7 @@ esac
 # Here we must recognize all the valid KERNEL-OS combinations.
 maybe_os=`echo $1 | sed 's/^\(.*\)-\([^-]*-[^-]*\)$/\2/'`
 case $maybe_os in
-  nto-qnx* | linux-gnu* | linux-dietlibc | linux-newlib* | linux-uclibc* | \
+  nto-qnx* | linux-gnu* | linux-dietlibc | linux-newlib* | linux-uclibc* | linux-musl* | \
   uclinux-uclibc* | uclinux-gnu* | kfreebsd*-gnu* | knetbsd*-gnu* | netbsd*-gnu* | \
   storm-chaos* | os2-emx* | rtmk-nova*)
     os=-$maybe_os
@@ -1211,7 +1211,7 @@ case $os in
 	      | -udi* | -eabi* | -lites* | -ieee* | -go32* | -aux* \
 	      | -chorusos* | -chorusrdb* \
 	      | -cygwin* | -pe* | -psos* | -moss* | -proelf* | -rtems* \
-	      | -mingw32* | -linux-gnu* | -linux-newlib* | -linux-uclibc* \
+	      | -mingw32* | -linux-gnu* | -linux-newlib* | -linux-uclibc* | -linux-musl* \
 	      | -uxpv* | -beos* | -mpeix* | -udk* \
 	      | -interix* | -uwin* | -mks* | -rhapsody* | -darwin* | -opened* \
 	      | -openstep* | -oskit* | -conix* | -pw32* | -nonstopux* \
diff --git a/fixincludes/mkfixinc.sh b/fixincludes/mkfixinc.sh
index ef048f7..f1cb8a5 100755
--- a/fixincludes/mkfixinc.sh
+++ b/fixincludes/mkfixinc.sh
@@ -28,7 +28,8 @@ case $machine in
     powerpc-*-eabi*    | \
     powerpc-*-rtems*   | \
     powerpcle-*-eabisim* | \
-    powerpcle-*-eabi* )
+    powerpcle-*-eabi* | \
+    *-musl* )
 	#  IF there is no include fixing,
 	#  THEN create a no-op fixer and exit
 	(echo "#! /bin/sh" ; echo "exit 0" ) > ${target}
diff --git a/gcc/config.gcc b/gcc/config.gcc
index 9a142e2..25136b7 100644
--- a/gcc/config.gcc
+++ b/gcc/config.gcc
@@ -468,11 +468,14 @@ case ${target} in
   esac
   tmake_file="t-slibgcc-elf-ver t-linux"
   case ${target} in
+    *-*-*musl*)
+      tm_defines="${tm_defines} UCLIBC_DEFAULT=0 MUSL_DEFAULT=1"
+      ;;
     *-*-*uclibc*)
-      tm_defines="${tm_defines} UCLIBC_DEFAULT=1"
+      tm_defines="${tm_defines} UCLIBC_DEFAULT=1 MUSL_DEFAULT=0"
       ;;
     *)
-      tm_defines="${tm_defines} UCLIBC_DEFAULT=0"
+      tm_defines="${tm_defines} UCLIBC_DEFAULT=0 MUSL_DEFAULT=0"
       ;;
   esac
   # Assume that glibc or uClibc are being used and so __cxa_atexit is provided.
diff --git a/gcc/config/arm/linux-eabi.h b/gcc/config/arm/linux-eabi.h
index 6612f74..f2ce735 100644
--- a/gcc/config/arm/linux-eabi.h
+++ b/gcc/config/arm/linux-eabi.h
@@ -55,6 +55,23 @@
 #undef GLIBC_DYNAMIC_LINKER
 #define GLIBC_DYNAMIC_LINKER "/lib/ld-linux.so.3"
 
+/* For ARM musl currently supports four dynamic linkers:
+   - ld-musl-arm.so.1 - for the EABI-derived soft-float ABI
+   - ld-musl-armhf.so.1 - for the EABI-derived hard-float ABI
+   - ld-musl-armeb.so.1 - for the EABI-derived soft-float ABI, EB
+   - ld-musl-armebhf.so.1 - for the EABI-derived hard-float ABI, EB
+   musl does not support the legacy OABI mode.
+   All the dynamic linkers live in /lib.
+   We default to soft-float, EL. */
+#undef  MUSL_DYNAMIC_LINKER
+#if TARGET_BIG_ENDIAN_DEFAULT
+#define MUSL_DYNAMIC_LINKER_E "%{mlittle-endian:;:eb}"
+#else
+#define MUSL_DYNAMIC_LINKER_E "%{mbig-endian:eb}"
+#endif
+#define MUSL_DYNAMIC_LINKER \
+  "/lib/ld-musl-arm" MUSL_DYNAMIC_LINKER_E "%{mfloat-abi=hard:hf}.so.1"
+
 /* At this point, bpabi.h will have clobbered LINK_SPEC.  We want to
    use the GNU/Linux version, not the generic BPABI version.  */
 #undef LINK_SPEC
diff --git a/gcc/config/i386/linux.h b/gcc/config/i386/linux.h
index 7eb2395..213b586 100644
--- a/gcc/config/i386/linux.h
+++ b/gcc/config/i386/linux.h
@@ -103,6 +103,9 @@ Boston, MA 02110-1301, USA.  */
 #define LINK_EMULATION "elf_i386"
 #define GLIBC_DYNAMIC_LINKER "/lib/ld-linux.so.2"
 
+#undef MUSL_DYNAMIC_LINKER
+#define MUSL_DYNAMIC_LINKER "/lib/ld-musl-i386.so.1"
+
 #undef  SUBTARGET_EXTRA_SPECS
 #define SUBTARGET_EXTRA_SPECS \
   { "link_emulation", LINK_EMULATION },\
diff --git a/gcc/config/i386/linux64.h b/gcc/config/i386/linux64.h
index cc8ed16..f0f025e 100644
--- a/gcc/config/i386/linux64.h
+++ b/gcc/config/i386/linux64.h
@@ -52,6 +52,13 @@ Boston, MA 02110-1301, USA.  */
 #define GLIBC_DYNAMIC_LINKER32 "/lib/ld-linux.so.2"
 #define GLIBC_DYNAMIC_LINKER64 "/lib64/ld-linux-x86-64.so.2"
 
+#undef MUSL_DYNAMIC_LINKER32
+#define MUSL_DYNAMIC_LINKER32 "/lib/ld-musl-i386.so.1"
+#undef MUSL_DYNAMIC_LINKER64
+#define MUSL_DYNAMIC_LINKER64 "/lib/ld-musl-x86_64.so.1"
+#undef MUSL_DYNAMIC_LINKERX32
+#define MUSL_DYNAMIC_LINKERX32 "/lib/ld-musl-x32.so.1"
+
 #undef	LINK_SPEC
 #define LINK_SPEC "%{!m32:-m elf_x86_64} %{m32:-m elf_i386} \
   %{shared:-shared} \
diff --git a/gcc/config/linux.h b/gcc/config/linux.h
index 59e3e85..1967b46 100644
--- a/gcc/config/linux.h
+++ b/gcc/config/linux.h
@@ -102,10 +102,12 @@ Boston, MA 02110-1301, USA.  */
 /* Determine which dynamic linker to use depending on whether GLIBC or
    uClibc is the default C library and whether -muclibc or -mglibc has
    been passed to change the default.  */
-#if UCLIBC_DEFAULT
-#define CHOOSE_DYNAMIC_LINKER(G, U) "%{mglibc:%{muclibc:%e-mglibc and -muclibc used together}" G ";:" U "}"
+#if MUSL_DEFAULT
+#define CHOOSE_DYNAMIC_LINKER(G, U, M) "%{mglibc:" G ";muclibc:" U ";:" M "}"
+#elif UCLIBC_DEFAULT
+#define CHOOSE_DYNAMIC_LINKER(G, U, M) "%{mglibc:" G ";mmusl:" M ";:" U "}"
 #else
-#define CHOOSE_DYNAMIC_LINKER(G, U) "%{muclibc:%{mglibc:%e-mglibc and -muclibc used together}" U ";:" G "}"
+#define CHOOSE_DYNAMIC_LINKER(G, U, M) "%{mmusl:" M ";muclibc:" U ";:" G "}"
 #endif
 
 /* For most targets the following definitions suffice;
@@ -115,15 +117,89 @@ Boston, MA 02110-1301, USA.  */
 #define UCLIBC_DYNAMIC_LINKER "/lib/ld-uClibc.so.0"
 #define UCLIBC_DYNAMIC_LINKER32 "/lib/ld-uClibc.so.0"
 #define UCLIBC_DYNAMIC_LINKER64 "/lib/ld64-uClibc.so.0"
+/* Should be redefined for each target that supports musl.  */
+#define MUSL_DYNAMIC_LINKER "/dev/null"
+#define MUSL_DYNAMIC_LINKER32 "/dev/null"
+#define MUSL_DYNAMIC_LINKER64 "/dev/null"
+#define MUSL_DYNAMIC_LINKERX32 "/dev/null"
+
 #define LINUX_DYNAMIC_LINKER \
-  CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER, UCLIBC_DYNAMIC_LINKER)
+  CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER, UCLIBC_DYNAMIC_LINKER, MUSL_DYNAMIC_LINKER)
 #define LINUX_DYNAMIC_LINKER32 \
-  CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER32, UCLIBC_DYNAMIC_LINKER32)
+  CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER32, UCLIBC_DYNAMIC_LINKER32, MUSL_DYNAMIC_LINKER32)
 #define LINUX_DYNAMIC_LINKER64 \
-  CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER64, UCLIBC_DYNAMIC_LINKER64)
+  CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER64, UCLIBC_DYNAMIC_LINKER64, MUSL_DYNAMIC_LINKER64)
 
 /* Determine whether the entire c99 runtime
    is present in the runtime library.  */
 #define TARGET_C99_FUNCTIONS (OPTION_GLIBC)
 
 #define TARGET_POSIX_IO
+
+/* musl avoids problematic includes by rearranging the include directories.
+ * Unfortunately, this is mostly duplicated from cppdefault.c */
+#if MUSL_DEFAULT
+#define INCLUDE_DEFAULTS_MUSL_GPP			\
+    { GPLUSPLUS_INCLUDE_DIR, "G++", 1, 1, 0, 0 },	\
+    { GPLUSPLUS_TOOL_INCLUDE_DIR, "G++", 1, 1, 0, 1 },	\
+    { GPLUSPLUS_BACKWARD_INCLUDE_DIR, "G++", 1, 1, 0, 0 },
+
+#ifdef LOCAL_INCLUDE_DIR
+#define INCLUDE_DEFAULTS_MUSL_LOCAL			\
+    { LOCAL_INCLUDE_DIR, 0, 0, 1, 1, 2 },		\
+    { LOCAL_INCLUDE_DIR, 0, 0, 1, 1, 0 },
+#else
+#define INCLUDE_DEFAULTS_MUSL_LOCAL
+#endif
+
+#ifdef PREFIX_INCLUDE_DIR
+#define INCLUDE_DEFAULTS_MUSL_PREFIX			\
+    { PREFIX_INCLUDE_DIR, 0, 0, 1, 0, 0},
+#else
+#define INCLUDE_DEFAULTS_MUSL_PREFIX
+#endif
+
+#ifdef CROSS_INCLUDE_DIR
+#define INCLUDE_DEFAULTS_MUSL_CROSS			\
+    { CROSS_INCLUDE_DIR, "GCC", 0, 0, 0, 0},
+#else
+#define INCLUDE_DEFAULTS_MUSL_CROSS
+#endif
+
+#ifdef TOOL_INCLUDE_DIR
+#define INCLUDE_DEFAULTS_MUSL_TOOL			\
+    { TOOL_INCLUDE_DIR, "BINUTILS", 0, 1, 0, 0},
+#else
+#define INCLUDE_DEFAULTS_MUSL_TOOL
+#endif
+
+#ifdef NATIVE_SYSTEM_HEADER_DIR
+#define INCLUDE_DEFAULTS_MUSL_NATIVE			\
+    { NATIVE_SYSTEM_HEADER_DIR, 0, 0, 0, 1, 2 },	\
+    { NATIVE_SYSTEM_HEADER_DIR, 0, 0, 0, 1, 0 },
+#else
+#define INCLUDE_DEFAULTS_MUSL_NATIVE
+#endif
+
+#if defined (CROSS_DIRECTORY_STRUCTURE) && !defined (TARGET_SYSTEM_ROOT)
+# undef INCLUDE_DEFAULTS_MUSL_LOCAL
+# define INCLUDE_DEFAULTS_MUSL_LOCAL
+# undef INCLUDE_DEFAULTS_MUSL_NATIVE
+# define INCLUDE_DEFAULTS_MUSL_NATIVE
+#else
+# undef INCLUDE_DEFAULTS_MUSL_CROSS
+# define INCLUDE_DEFAULTS_MUSL_CROSS
+#endif
+
+#undef INCLUDE_DEFAULTS
+#define INCLUDE_DEFAULTS				\
+  {							\
+    INCLUDE_DEFAULTS_MUSL_GPP				\
+    INCLUDE_DEFAULTS_MUSL_PREFIX			\
+    INCLUDE_DEFAULTS_MUSL_CROSS				\
+    INCLUDE_DEFAULTS_MUSL_TOOL				\
+    INCLUDE_DEFAULTS_MUSL_NATIVE			\
+    { GCC_INCLUDE_DIR, "GCC", 0, 1, 0, 0 },		\
+    { 0, 0, 0, 0, 0, 0 }				\
+  }
+#endif
diff --git a/gcc/config/linux.opt b/gcc/config/linux.opt
index 3f615bb..31fb21b 100644
--- a/gcc/config/linux.opt
+++ b/gcc/config/linux.opt
@@ -27,3 +27,7 @@ Use uClibc instead of GNU libc
 mglibc
 Target RejectNegative Report InverseMask(UCLIBC, GLIBC) Var(linux_uclibc) VarExists
 Use GNU libc instead of uClibc
+
+mmusl
+Target RejectNegative Report Var(linux_musl)
+Use musl C library
diff --git a/gcc/config/mips/linux.h b/gcc/config/mips/linux.h
index ff268d4..97bfc38 100644
--- a/gcc/config/mips/linux.h
+++ b/gcc/config/mips/linux.h
@@ -179,3 +179,9 @@ Boston, MA 02110-1301, USA.  */
   %{profile:-lc_p} %{!profile: -lc}}"
 
 #define MD_UNWIND_SUPPORT "config/mips/linux-unwind.h"
+
+#undef MUSL_DYNAMIC_LINKER32
+#define MUSL_DYNAMIC_LINKER32 "/lib/ld-musl-mips%{EL:el}%{msoft-float:-sf}.so.1"
+#undef MUSL_DYNAMIC_LINKER64
+#define MUSL_DYNAMIC_LINKER64 "/lib/ld-musl-mips64%{EL:el}%{msoft-float:-sf}.so.1"
+#define MUSL_DYNAMIC_LINKERN32 "/lib/ld-musl-mipsn32%{EL:el}%{msoft-float:-sf}.so.1"
diff --git a/gcc/config/sh/linux-unwind.h b/gcc/config/sh/linux-unwind.h
index de84a77..98d1661 100644
--- a/gcc/config/sh/linux-unwind.h
+++ b/gcc/config/sh/linux-unwind.h
@@ -80,10 +80,10 @@ shmedia_fallback_frame_state (struct _Unwind_Context *context,
 	   && (*(unsigned long *) (pc+11)  == 0x6ff0fff0))
     {
       struct rt_sigframe {
-	struct siginfo *pinfo;
+	siginfo_t *pinfo;
 	void *puc;
-	struct siginfo info;
-	struct ucontext uc;
+	siginfo_t info;
+	ucontext_t uc;
       } *rt_ = context->cfa;
       /* The void * cast is necessary to avoid an aliasing warning.
          The aliasing warning is correct, but should not be a problem
@@ -179,8 +179,8 @@ sh_fallback_frame_state (struct _Unwind_Context *context,
 		&& (*(unsigned short *) (pc+14)  == 0x00ad))))
     {
       struct rt_sigframe {
-	struct siginfo info;
-	struct ucontext uc;
+	siginfo_t info;
+	ucontext_t uc;
       } *rt_ = context->cfa;
       /* The void * cast is necessary to avoid an aliasing warning.
          The aliasing warning is correct, but should not be a problem
diff --git a/gcc/config/sh/linux.h b/gcc/config/sh/linux.h
index 94c3166..306a08c 100644
--- a/gcc/config/sh/linux.h
+++ b/gcc/config/sh/linux.h
@@ -48,6 +48,29 @@ Boston, MA 02110-1301, USA.  */
 
 #define TARGET_ASM_FILE_END file_end_indicate_exec_stack
 
+#if TARGET_ENDIAN_DEFAULT == MASK_LITTLE_ENDIAN
+#define MUSL_DYNAMIC_LINKER_E "%{mb:eb}"
+#else
+#define MUSL_DYNAMIC_LINKER_E "%{!ml:eb}"
+#endif
+
+#if TARGET_CPU_DEFAULT & ( MASK_HARD_SH2A_DOUBLE | MASK_SH4 )
+/* "-nofpu" if any nofpu option is specified */
+#define MUSL_DYNAMIC_LINKER_FP \
+  "%{m1|m2|m2a-nofpu|m3|m4-nofpu|m4-100-nofpu|m4-200-nofpu|m4-300-nofpu|" \
+  "m4-340|m4-400|m4-500|m4al|m5-32media-nofpu|m5-64media-nofpu|" \
+  "m5-compact-nofpu:-nofpu}"
+#else
+/* "-nofpu" if none of the hard fpu options are specified */
+#define MUSL_DYNAMIC_LINKER_FP \
+  "%{m2a|m4|m4-100|m4-200|m4-300|m4a|m5-32media|m5-64media|m5-compact:;:-nofpu}"
+#endif
+
+#undef MUSL_DYNAMIC_LINKER
+#define MUSL_DYNAMIC_LINKER \
+  "/lib/ld-musl-sh" MUSL_DYNAMIC_LINKER_E MUSL_DYNAMIC_LINKER_FP \
+  "%{mfdpic:-fdpic}.so.1"
+
 #define GLIBC_DYNAMIC_LINKER "/lib/ld-linux.so.2"
 
 #undef SUBTARGET_LINK_EMUL_SUFFIX
diff --git a/gcc/unwind-dw2-fde-glibc.c b/gcc/unwind-dw2-fde-glibc.c
index 25bf2bb..59f7615 100644
--- a/gcc/unwind-dw2-fde-glibc.c
+++ b/gcc/unwind-dw2-fde-glibc.c
@@ -49,7 +49,7 @@
 #include "gthr.h"
 
 #if !defined(inhibit_libc) && defined(HAVE_LD_EH_FRAME_HDR) \
-    && (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2) \
+    && (!defined(__GLIBC__) || __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ > 2) \
 	|| (__GLIBC__ == 2 && __GLIBC_MINOR__ == 2 && defined(DT_CONFIG)))
 
 #ifndef __RELOC_POINTER
diff --git a/libstdc++-v3/config/os/generic/os_defines.h b/libstdc++-v3/config/os/generic/os_defines.h
index bcc533c..a9bfded 100644
--- a/libstdc++-v3/config/os/generic/os_defines.h
+++ b/libstdc++-v3/config/os/generic/os_defines.h
@@ -38,4 +38,9 @@
 // System-specific #define, typedefs, corrections, etc, go here.  This
 // file will come before all others.
 
+// Disable the weak reference logic in gthr.h for os/generic because it
+// is broken on every platform unless there is implementation specific
+// workaround in gthr-posix.h and at link-time for static linking.
+#define _GLIBCXX_GTHREAD_USE_WEAK 0
+
 #endif
diff --git a/libstdc++-v3/configure.host b/libstdc++-v3/configure.host
index 441eb4c..37e80ab 100644
--- a/libstdc++-v3/configure.host
+++ b/libstdc++-v3/configure.host
@@ -210,6 +210,9 @@ case "${host_os}" in
   freebsd*)
     os_include_dir="os/bsd/freebsd"
     ;;
+  linux-musl*)
+    os_include_dir="os/generic"
+    ;;
   gnu* | linux* | kfreebsd*-gnu | knetbsd*-gnu)
     if [ "$uclibc" = "yes" ]; then
       os_include_dir="os/uclibc"