Bug 1571596 - Reduce the number of toolchain scripts for GCC. r=nalexander

Now that all GCC and related source tarballs extract to paths
independent of their version number, the scripts are all very
look-alike, so they can be consolidated.

Differential Revision: https://phabricator.services.mozilla.com/D40749

taskcluster/ci/toolchain/gcc.yml

@@ -16,7 +16,7 @@ linux64-gcc-6:
     treeherder:
         symbol: TL(gcc6)
     run:
-        script: build-gcc-6-linux.sh
+        script: build-gcc-linux.sh
         toolchain-alias: linux64-gcc
     fetches:
         fetch:
@@ -32,7 +32,7 @@ linux64-gcc-7:
     treeherder:
         symbol: TL(gcc7)
     run:
-        script: build-gcc-7-linux.sh
+        script: build-gcc-linux.sh
     fetches:
         fetch:
             - binutils-2.31.1
@@ -47,7 +47,7 @@ linux64-gcc-8:
     treeherder:
         symbol: TL(gcc8)
     run:
-        script: build-gcc-8-linux.sh
+        script: build-gcc-linux.sh
     fetches:
         fetch:
             - binutils-2.31.1
@@ -62,7 +62,7 @@ linux64-gcc-9:
     treeherder:
         symbol: TL(gcc9)
     run:
-        script: build-gcc-9-linux.sh
+        script: build-gcc-linux.sh
     fetches:
         fetch:
             - binutils-2.31.1

taskcluster/scripts/misc/build-gcc-7-linux.sh

@@ -1,23 +0,0 @@
-#!/bin/bash
-set -e
-
-# This script is for building GCC 7 for Linux.
-
-root_dir=$MOZ_FETCHES_DIR
-data_dir=$GECKO_PATH/build/unix/build-gcc
-
-. $data_dir/build-gcc.sh
-
-pushd $root_dir/gcc-source
-ln -sf ../gmp-source gmp
-ln -sf ../isl-source isl
-ln -sf ../mpc-source mpc
-ln -sf ../mpfr-source mpfr
-popd
-
-build_binutils
-build_gcc
-
-# Put a tarball in the artifacts dir
-mkdir -p $UPLOAD_DIR
-cp $MOZ_FETCHES_DIR/gcc.tar.* $UPLOAD_DIR

taskcluster/scripts/misc/build-gcc-8-linux.sh

@@ -1,23 +0,0 @@
-#!/bin/bash
-set -e
-
-# This script is for building GCC 7 for Linux.
-
-root_dir=$MOZ_FETCHES_DIR
-data_dir=$GECKO_PATH/build/unix/build-gcc
-
-. $data_dir/build-gcc.sh
-
-pushd $root_dir/gcc-source
-ln -sf ../gmp-source gmp
-ln -sf ../isl-source isl
-ln -sf ../mpc-source mpc
-ln -sf ../mpfr-source mpfr
-popd
-
-build_binutils
-build_gcc
-
-# Put a tarball in the artifacts dir
-mkdir -p $UPLOAD_DIR
-cp $MOZ_FETCHES_DIR/gcc.tar.* $UPLOAD_DIR

taskcluster/scripts/misc/build-gcc-9-linux.sh

@@ -1,23 +0,0 @@
-#!/bin/bash
-set -e
-
-# This script is for building GCC 7 for Linux.
-
-root_dir=$MOZ_FETCHES_DIR
-data_dir=$GECKO_PATH/build/unix/build-gcc
-
-. $data_dir/build-gcc.sh
-
-pushd $root_dir/gcc-source
-ln -sf ../gmp-source gmp
-ln -sf ../isl-source isl
-ln -sf ../mpc-source mpc
-ln -sf ../mpfr-source mpfr
-popd
-
-build_binutils
-build_gcc
-
-# Put a tarball in the artifacts dir
-mkdir -p $UPLOAD_DIR
-cp $MOZ_FETCHES_DIR/gcc.tar.* $UPLOAD_DIR

taskcluster/scripts/misc/build-gcc-linux.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
 set -e
 
-# This script is for building GCC 6 for Linux.
+# This script is for building GCC for Linux.
 
 root_dir=$MOZ_FETCHES_DIR
 data_dir=$GECKO_PATH/build/unix/build-gcc