gcc: fix libgomp relocation. Patch applied from @ioraff

Closes #138

core/gcc/build

@@ -1,5 +1,7 @@
 #!/bin/sh -e
 
+patch -p1 < invalid_tls_model.patch
+
 # Make sure gmp is built with generic options.
 cp -v gcc/gmp/configfsf.guess gcc/gmp/config.guess
 cp -v gcc/gmp/configfsf.sub   gcc/gmp/config.sub

core/gcc/checksums

@@ -3,3 +3,4 @@ ea6ef08f121239da5695f76c9b33637a118dcf63e24164422231917fa61fb206  gcc-9.2.0.tar.
 1d3be708604eae0e42d578ba93b390c2a145f17743a744d8f3f8c2ad5855a38a  mpfr-4.0.2.tar.xz
 6985c538143c1208dcb1ac42cedad6ff52e267b47e5f970183a3e75125b43c2e  mpc-1.1.0.tar.gz
 765614b3396d70bca3fa0ae4a813632486c6dca320e2bd13c8c39dca52be4a4c  c99
+b0bf792c3f5278e768b7199cc94e8c57e364eb0b70dc5a226d47eb9e25e1dac9  invalid_tls_model.patch

core/gcc/patches/invalid_tls_model.patch

@@ -0,0 +1,26 @@
+--- a/gcc/libgomp/configure.tgt	2018-11-08 18:13:04.000000000 +0100
++++ b/gcc/libgomp/configure.tgt	2019-06-29 20:06:31.972950350 +0200
+@@ -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="${XCFLAGS} -ftls-model=initial-exec -DUSING_INITIAL_EXEC_TLS"
+-	;;
+-
+-    *-*-rtems*)
+-	XCFLAGS="${XCFLAGS} -ftls-model=local-exec"
+-	;;
+-  esac
+-fi
+-
+ # Since we require POSIX threads, assume a POSIX system by default.
+ config_path="posix"
+

core/gcc/sources

@@ -3,3 +3,4 @@ https://gmplib.org/download/gmp/gmp-6.1.2.tar.xz gcc/gmp
 https://ftp.gnu.org/gnu/mpfr/mpfr-4.0.2.tar.xz gcc/mpfr
 https://ftp.gnu.org/gnu/mpc/mpc-1.1.0.tar.gz gcc/mpc
 files/c99
+patches/invalid_tls_model.patch