add patches to fix invalid tls-model usage in gcc target libs

the initial-exec tls model is not valid in any code that might be
dynamically loaded. it usually happens to work on glibc because glibc
reserves some static tls space for late-loaded libraries that need it,
but if it's already been exhausted that will fail. musl does not
support this hack at all, and it's not valid for gcc target libs to be
doing it anywhere, so patch it out entirely rather than just for musl.

patches/gcc-5.3.0/0016-invalid_tls_model.diff

@@ -0,0 +1,51 @@
+--- gcc-7.3.0/libgomp/configure.tgt.orig	2018-09-25 13:44:16.654561098 -0400
++++ gcc-7.3.0/libgomp/configure.tgt	2018-09-25 13:44:50.452688100 -0400
+@@ -10,23 +10,6 @@
+ #  XCFLAGS		Add extra compile flags to use.
+ #  XLDFLAGS		Add extra link flags to use.
+ 
+-# Optimize TLS usage by avoiding the overhead of dynamic allocation.
+-if test $gcc_cv_have_tls = yes ; then
+-  case "${target}" in
+-
+-    *-*-k*bsd*-gnu*)
+-	;;
+-
+-    *-*-linux* | *-*-gnu*)
+-	XCFLAGS="${XCFLAGS} -ftls-model=initial-exec"
+-	;;
+-
+-    *-*-rtems*)
+-	XCFLAGS="${XCFLAGS} -ftls-model=local-exec"
+-	;;
+-  esac
+-fi
+-
+ # Since we require POSIX threads, assume a POSIX system by default.
+ config_path="posix"
+ 
+--- gcc-7.3.0/libitm/configure.tgt.orig	2018-09-25 13:47:31.019296903 -0400
++++ gcc-7.3.0/libitm/configure.tgt	2018-09-25 13:47:37.676322335 -0400
+@@ -27,22 +27,6 @@
+ #  XCFLAGS		Add extra compile flags to use.
+ #  XLDFLAGS		Add extra link flags to use.
+ 
+-# Optimize TLS usage by avoiding the overhead of dynamic allocation.
+-if test "$gcc_cv_have_tls" = yes ; then
+-  case "${target}" in
+-
+-    # For x86, we use slots in the TCB head for most of our TLS.
+-    # The setup of those slots in beginTransaction can afford to
+-    # use the global-dynamic model.
+-    i[456]86-*-linux* | x86_64-*-linux*)
+-	;;
+-    
+-    *-*-linux*)
+-	XCFLAGS="${XCFLAGS} -ftls-model=initial-exec"
+-	;;
+-  esac
+-fi
+-
+ # Map the target cpu to an ARCH sub-directory.  At the same time,
+ # work out any special compilation flags as necessary.
+ case "${target_cpu}" in

patches/gcc-6.4.0/0016-invalid_tls_model.diff

@@ -0,0 +1,51 @@
+--- gcc-7.3.0/libgomp/configure.tgt.orig	2018-09-25 13:44:16.654561098 -0400
++++ gcc-7.3.0/libgomp/configure.tgt	2018-09-25 13:44:50.452688100 -0400
+@@ -10,23 +10,6 @@
+ #  XCFLAGS		Add extra compile flags to use.
+ #  XLDFLAGS		Add extra link flags to use.
+ 
+-# Optimize TLS usage by avoiding the overhead of dynamic allocation.
+-if test $gcc_cv_have_tls = yes ; then
+-  case "${target}" in
+-
+-    *-*-k*bsd*-gnu*)
+-	;;
+-
+-    *-*-linux* | *-*-gnu*)
+-	XCFLAGS="${XCFLAGS} -ftls-model=initial-exec"
+-	;;
+-
+-    *-*-rtems*)
+-	XCFLAGS="${XCFLAGS} -ftls-model=local-exec"
+-	;;
+-  esac
+-fi
+-
+ # Since we require POSIX threads, assume a POSIX system by default.
+ config_path="posix"
+ 
+--- gcc-7.3.0/libitm/configure.tgt.orig	2018-09-25 13:47:31.019296903 -0400
++++ gcc-7.3.0/libitm/configure.tgt	2018-09-25 13:47:37.676322335 -0400
+@@ -27,22 +27,6 @@
+ #  XCFLAGS		Add extra compile flags to use.
+ #  XLDFLAGS		Add extra link flags to use.
+ 
+-# Optimize TLS usage by avoiding the overhead of dynamic allocation.
+-if test "$gcc_cv_have_tls" = yes ; then
+-  case "${target}" in
+-
+-    # For x86, we use slots in the TCB head for most of our TLS.
+-    # The setup of those slots in beginTransaction can afford to
+-    # use the global-dynamic model.
+-    i[456]86-*-linux* | x86_64-*-linux*)
+-	;;
+-    
+-    *-*-linux*)
+-	XCFLAGS="${XCFLAGS} -ftls-model=initial-exec"
+-	;;
+-  esac
+-fi
+-
+ # Map the target cpu to an ARCH sub-directory.  At the same time,
+ # work out any special compilation flags as necessary.
+ case "${target_cpu}" in

patches/gcc-7.3.0/0016-invalid_tls_model.diff

@@ -0,0 +1,51 @@
+--- gcc-7.3.0/libgomp/configure.tgt.orig	2018-09-25 13:44:16.654561098 -0400
++++ gcc-7.3.0/libgomp/configure.tgt	2018-09-25 13:44:50.452688100 -0400
+@@ -10,23 +10,6 @@
+ #  XCFLAGS		Add extra compile flags to use.
+ #  XLDFLAGS		Add extra link flags to use.
+ 
+-# Optimize TLS usage by avoiding the overhead of dynamic allocation.
+-if test $gcc_cv_have_tls = yes ; then
+-  case "${target}" in
+-
+-    *-*-k*bsd*-gnu*)
+-	;;
+-
+-    *-*-linux* | *-*-gnu*)
+-	XCFLAGS="${XCFLAGS} -ftls-model=initial-exec"
+-	;;
+-
+-    *-*-rtems*)
+-	XCFLAGS="${XCFLAGS} -ftls-model=local-exec"
+-	;;
+-  esac
+-fi
+-
+ # Since we require POSIX threads, assume a POSIX system by default.
+ config_path="posix"
+ 
+--- gcc-7.3.0/libitm/configure.tgt.orig	2018-09-25 13:47:31.019296903 -0400
++++ gcc-7.3.0/libitm/configure.tgt	2018-09-25 13:47:37.676322335 -0400
+@@ -27,22 +27,6 @@
+ #  XCFLAGS		Add extra compile flags to use.
+ #  XLDFLAGS		Add extra link flags to use.
+ 
+-# Optimize TLS usage by avoiding the overhead of dynamic allocation.
+-if test "$gcc_cv_have_tls" = yes ; then
+-  case "${target}" in
+-
+-    # For x86, we use slots in the TCB head for most of our TLS.
+-    # The setup of those slots in beginTransaction can afford to
+-    # use the global-dynamic model.
+-    i[456]86-*-linux* | x86_64-*-linux*)
+-	;;
+-    
+-    *-*-linux*)
+-	XCFLAGS="${XCFLAGS} -ftls-model=initial-exec"
+-	;;
+-  esac
+-fi
+-
+ # Map the target cpu to an ARCH sub-directory.  At the same time,
+ # work out any special compilation flags as necessary.
+ case "${target_cpu}" in