--- a/config.sub
+++ b/config.sub
@@ -125,6 +125,7 @@ esac
 maybe_os=`echo $1 | sed 's/^\(.*\)-\([^-]*-[^-]*\)$/\2/'`
 case $maybe_os in
   nto-qnx* | linux-gnu* | linux-android* | linux-dietlibc | linux-newlib* | \
+  linux-musl* | \
   linux-uclibc* | uclinux-uclibc* | uclinux-gnu* | kfreebsd*-gnu* | \
   knetbsd*-gnu* | netbsd*-gnu* | \
   kopensolaris*-gnu* | \
--- a/gcc/config/arm/linux-eabi.h
+++ b/gcc/config/arm/linux-eabi.h
@@ -63,6 +63,10 @@
 #undef  GLIBC_DYNAMIC_LINKER
 #define GLIBC_DYNAMIC_LINKER "/lib/ld-linux.so.3"
 
+/* musl has no "classic" (i.e. broken) mode */
+#undef  MUSL_DYNAMIC_LINKER
+#define MUSL_DYNAMIC_LINKER "/lib/ld-musl-arm.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
--- a/gcc/config/i386/linux.h
+++ b/gcc/config/i386/linux.h
@@ -101,6 +101,7 @@ along with GCC; see the file COPYING3.
 /* These macros may be overridden in k*bsd-gnu.h and i386/k*bsd-gnu.h. */
 #define LINK_EMULATION "elf_i386"
 #define GLIBC_DYNAMIC_LINKER "/lib/ld-linux.so.2"
+#define MUSL_DYNAMIC_LINKER "/lib/ld-musl-i386.so.1"
 
 #undef  ASM_SPEC
 #define ASM_SPEC \
--- a/gcc/config/i386/linux64.h
+++ b/gcc/config/i386/linux64.h
@@ -61,6 +61,9 @@ see the files COPYING3 and COPYING.RUNTI
 #define GLIBC_DYNAMIC_LINKER32 "/lib/ld-linux.so.2"
 #define GLIBC_DYNAMIC_LINKER64 "/lib64/ld-linux-x86-64.so.2"
 
+#define MUSL_DYNAMIC_LINKER32 "/lib/ld-musl-i386.so.1"
+#define MUSL_DYNAMIC_LINKER64 "/lib/ld-musl-x86_64.so.1"
+
 #if TARGET_64BIT_DEFAULT
 #define SPEC_32 "m32"
 #define SPEC_64 "!m32"
--- a/gcc/config/linux.h
+++ b/gcc/config/linux.h
@@ -86,6 +86,7 @@ see the files COPYING3 and COPYING.RUNTI
 #define OPTION_GLIBC  (linux_libc == LIBC_GLIBC)
 #define OPTION_UCLIBC (linux_libc == LIBC_UCLIBC)
 #define OPTION_BIONIC (linux_libc == LIBC_BIONIC)
+#define OPTION_MUSL   (linux_libc == LIBC_MUSL)
 
 #define LINUX_TARGET_OS_CPP_BUILTINS()				\
     do {							\
@@ -120,18 +121,21 @@ see the files COPYING3 and COPYING.RUNTI
    uClibc or Bionic is the default C library and whether
    -muclibc or -mglibc or -mbionic has been passed to change the default.  */
 
-#define CHOOSE_DYNAMIC_LINKER1(LIBC1, LIBC2, LIBC3, LD1, LD2, LD3)	\
-  "%{" LIBC2 ":" LD2 ";:%{" LIBC3 ":" LD3 ";:" LD1 "}}"
+#define CHOOSE_DYNAMIC_LINKER1(LIBC1, LIBC2, LIBC3, LIBC4, LD1, LD2, LD3, LD4)	\
+  "%{" LIBC2 ":" LD2 ";:%{" LIBC3 ":" LD3 ";:%{" LIBC4 ":" LD4 ";:" LD1 "}}}"
 
 #if DEFAULT_LIBC == LIBC_GLIBC
-#define CHOOSE_DYNAMIC_LINKER(G, U, B) \
-  CHOOSE_DYNAMIC_LINKER1 ("mglibc", "muclibc", "mbionic", G, U, B)
+#define CHOOSE_DYNAMIC_LINKER(G, U, B, M) \
+  CHOOSE_DYNAMIC_LINKER1 ("mglibc", "muclibc", "mbionic", "mmusl", G, U, B, M)
 #elif DEFAULT_LIBC == LIBC_UCLIBC
-#define CHOOSE_DYNAMIC_LINKER(G, U, B) \
-  CHOOSE_DYNAMIC_LINKER1 ("muclibc", "mglibc", "mbionic", U, G, B)
+#define CHOOSE_DYNAMIC_LINKER(G, U, B, M) \
+  CHOOSE_DYNAMIC_LINKER1 ("muclibc", "mglibc", "mbionic", "mmusl", U, G, B, M)
 #elif DEFAULT_LIBC == LIBC_BIONIC
-#define CHOOSE_DYNAMIC_LINKER(G, U, B) \
-  CHOOSE_DYNAMIC_LINKER1 ("mbionic", "mglibc", "muclibc", B, G, U)
+#define CHOOSE_DYNAMIC_LINKER(G, U, B, M) \
+  CHOOSE_DYNAMIC_LINKER1 ("mbionic", "mglibc", "muclibc", "mmusl", B, G, U, M)
+#elif DEFAULT_LIBC == LIBC_MUSL
+#define CHOOSE_DYNAMIC_LINKER(G, U, B, M) \
+  CHOOSE_DYNAMIC_LINKER1 ("mmusl", "mglibc", "muclibc", "mbionic", M, G, U, B)
 #else
 #error "Unsupported DEFAULT_LIBC"
 #endif /* DEFAULT_LIBC */
@@ -149,13 +153,13 @@ see the files COPYING3 and COPYING.RUNTI
 
 #define LINUX_DYNAMIC_LINKER						\
   CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER, UCLIBC_DYNAMIC_LINKER,	\
-			 BIONIC_DYNAMIC_LINKER)
+			 BIONIC_DYNAMIC_LINKER, MUSL_DYNAMIC_LINKER)
 #define LINUX_DYNAMIC_LINKER32						\
   CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER32, UCLIBC_DYNAMIC_LINKER32, \
-			 BIONIC_DYNAMIC_LINKER32)
+			 BIONIC_DYNAMIC_LINKER32, MUSL_DYNAMIC_LINKER32)
 #define LINUX_DYNAMIC_LINKER64						\
   CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKER64, UCLIBC_DYNAMIC_LINKER64, \
-			 BIONIC_DYNAMIC_LINKER64)
+			 BIONIC_DYNAMIC_LINKER64, MUSL_DYNAMIC_LINKER64)
 
 /* Determine whether the entire c99 runtime
    is present in the runtime library.  */
--- a/gcc/config/linux.opt
+++ b/gcc/config/linux.opt
@@ -30,3 +30,7 @@ Use GNU C library
 muclibc
 Target Report RejectNegative Var(linux_libc,LIBC_UCLIBC) VarExists Negative(mbionic)
 Use uClibc C library
+
+mmusl
+Target Report RejectNegative Var(linux_libc,LIBC_MUSL) Negative(mglibc)
+Use musl C library
--- a/gcc/config/mips/linux.h
+++ b/gcc/config/mips/linux.h
@@ -66,6 +66,8 @@ along with GCC; see the file COPYING3.
 
 #define GLIBC_DYNAMIC_LINKER "/lib/ld.so.1"
 
+#define MUSL_DYNAMIC_LINKER "/lib/ld-musl-mips.so.1"
+
 /* Borrowed from sparc/linux.h */
 #undef LINK_SPEC
 #define LINK_SPEC \
--- a/gcc/config/mips/linux64.h
+++ b/gcc/config/mips/linux64.h
@@ -39,8 +39,11 @@ along with GCC; see the file COPYING3.
 #define GLIBC_DYNAMIC_LINKER64 "/lib64/ld.so.1"
 #define GLIBC_DYNAMIC_LINKERN32 "/lib32/ld.so.1"
 #define UCLIBC_DYNAMIC_LINKERN32 "/lib32/ld-uClibc.so.0"
+#define MUSL_DYNAMIC_LINKERN32 "/lib32/ld-musl-mips.so.1"
+#define MUSL_DYNAMIC_LINKER32 "/lib32/ld-musl-mips.so.1"
+#define MUSL_DYNAMIC_LINKER64 "/lib64/ld-musl-mips.so.1"
 #define LINUX_DYNAMIC_LINKERN32 \
-  CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKERN32, UCLIBC_DYNAMIC_LINKERN32)
+  CHOOSE_DYNAMIC_LINKER (GLIBC_DYNAMIC_LINKERN32, UCLIBC_DYNAMIC_LINKERN32, MUSL_DYNAMIC_LINKERN32)
 
 #undef LINK_SPEC
 #define LINK_SPEC "\
--- a/gcc/config.gcc
+++ b/gcc/config.gcc
@@ -514,7 +514,7 @@ case ${target} in
       tmake_file="$tmake_file t-gnu";;
   esac
   # Common C libraries.
-  tm_defines="$tm_defines LIBC_GLIBC=1 LIBC_UCLIBC=2 LIBC_BIONIC=3"
+  tm_defines="$tm_defines LIBC_GLIBC=1 LIBC_UCLIBC=2 LIBC_BIONIC=3 LIBC_MUSL=4"
   # glibc / uclibc / bionic switch.
   # uclibc and bionic aren't usable for GNU/Hurd and neither for GNU/k*BSD.
   case $target in
@@ -530,6 +530,9 @@ case ${target} in
     *-*-*uclibc*)
       tm_defines="$tm_defines DEFAULT_LIBC=LIBC_UCLIBC"
       ;;
+    *-*-*musl*)
+      tm_defines="$tm_defines DEFAULT_LIBC=LIBC_MUSL"
+      ;;
     *)
       tm_defines="$tm_defines DEFAULT_LIBC=LIBC_GLIBC"
       ;;
--- a/gcc/ginclude/stddef.h
+++ b/gcc/ginclude/stddef.h
@@ -183,6 +183,7 @@ typedef __PTRDIFF_TYPE__ ptrdiff_t;
 #ifndef _GCC_SIZE_T
 #ifndef _SIZET_
 #ifndef __size_t
+#ifndef __DEFINED_size_t /* musl */
 #define __size_t__	/* BeOS */
 #define __SIZE_T__	/* Cray Unicos/Mk */
 #define _SIZE_T
@@ -199,6 +200,7 @@ typedef __PTRDIFF_TYPE__ ptrdiff_t;
 #define ___int_size_t_h
 #define _GCC_SIZE_T
 #define _SIZET_
+#define __DEFINED_size_t /* musl */
 #if defined (__FreeBSD__) && (__FreeBSD__ >= 5)
 /* __size_t is a typedef on FreeBSD 5!, must not trash it. */
 #else
@@ -213,6 +215,7 @@ typedef __SIZE_TYPE__ size_t;
 typedef long ssize_t;
 #endif /* __BEOS__ */
 #endif /* !(defined (__GNUG__) && defined (size_t)) */
+#endif /* __DEFINED_size_t */
 #endif /* __size_t */
 #endif /* _SIZET_ */
 #endif /* _GCC_SIZE_T */
--- a/libgomp/config/posix/time.c
+++ b/libgomp/config/posix/time.c
@@ -28,6 +28,8 @@
    The following implementation uses the most simple POSIX routines.
    If present, POSIX 4 clocks should be used instead.  */
 
+#define _POSIX_C_SOURCE 199309L /* for clocks */
+
 #include "libgomp.h"
 #include <unistd.h>
 #if TIME_WITH_SYS_TIME
--- a/libstdc++-v3/configure.host
+++ b/libstdc++-v3/configure.host
@@ -236,6 +236,13 @@ case "${host_os}" in
     os_include_dir="os/bsd/freebsd"
     ;;
   gnu* | linux* | kfreebsd*-gnu | knetbsd*-gnu)
+    # check for musl by target
+    case "${host_os}" in
+      *-musl*)
+        os_include_dir="os/generic"
+        ;;
+      *)
+
     if [ "$uclibc" = "yes" ]; then
       os_include_dir="os/uclibc"
     elif [ "$bionic" = "yes" ]; then
@@ -244,6 +251,9 @@ case "${host_os}" in
       os_include_dir="os/gnu-linux"
     fi
     ;;
+
+    esac
+    ;;
   hpux*)
     os_include_dir="os/hpux"
     ;;