[binutils-gdb] gdb: fix shellcheck warnings SC2006 (use $() instead of ``) in gdbarch.sh

[gdb-buildbot@sergiodj.net]

*** TEST RESULTS FOR COMMIT cb02ab2416c2d83ca053652a21788189f3f7779f ***

commit cb02ab2416c2d83ca053652a21788189f3f7779f
Author:     Simon Marchi <simon.marchi@efficios.com>
AuthorDate: Wed Apr 29 20:35:34 2020 -0400
Commit:     Simon Marchi <simon.marchi@efficios.com>
CommitDate: Wed Apr 29 20:35:34 2020 -0400

    gdb: fix shellcheck warnings SC2006 (use $() instead of ``) in gdbarch.sh
    
    Fix all instances of:
    
        In gdbarch.sh line 2195:
                printf "            `echo "$function" | sed -e 's/./ /g'`  %s %s)\n" "$returntype" "$function"
                                    ^-- SC2006: Use $(...) notation instead of legacy backticked `...`.
    
        Did you mean:
                printf "            $(echo "$function" | sed -e 's/./ /g')  %s %s)\n" "$returntype" "$function"
    
    See here [1] for the rationale.
    
    [1] https://github.com/koalaman/shellcheck/wiki/SC2006
    
    gdb/ChangeLog:
    
            * gdbarch.sh: Use $(...) instead of `...`.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index eefeac4c18..d751c052ce 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,7 @@
+2020-04-29  Simon Marchi  <simon.marchi@efficios.com>
+
+	* gdbarch.sh: Use $(...) instead of `...`.
+
 2020-04-29  Simon Marchi  <simon.marchi@efficios.com>
 
 	* gdbarch.sh: Use double quotes around variables.
diff --git a/gdb/gdbarch.sh b/gdb/gdbarch.sh
index a934a7aa6b..0e89bd1900 100755
--- a/gdb/gdbarch.sh
+++ b/gdb/gdbarch.sh
@@ -67,7 +67,7 @@ ${line}"
 	    # The semantics of IFS varies between different SH's.  Some
 	    # treat ``;;' as three fields while some treat it as just two.
 	    # Work around this by eliminating ``;;'' ....
-	    line="`echo "${line}" | sed -e 's/;;/; ;/g' -e 's/;;/; ;/g'`"
+	    line="$(echo "${line}" | sed -e 's/;;/; ;/g' -e 's/;;/; ;/g')"
 
 	    OFS="${IFS}" ; IFS="[;]"
 	    eval read "${read}" <<EOF
@@ -2162,7 +2162,7 @@ do
 	printf "\n"
 	printf "void\n"
 	printf "set_gdbarch_%s (struct gdbarch *gdbarch,\n" "$function"
-        printf "            `echo "$function" | sed -e 's/./ /g'`  gdbarch_%s_ftype %s)\n" "$function" "$function"
+	printf "            %s  gdbarch_%s_ftype %s)\n" "$(echo "$function" | sed -e 's/./ /g')" "$function" "$function"
 	printf "{\n"
 	printf "  gdbarch->%s = %s;\n" "$function" "$function"
 	printf "}\n"
@@ -2192,7 +2192,7 @@ do
 	printf "\n"
 	printf "void\n"
 	printf "set_gdbarch_%s (struct gdbarch *gdbarch,\n" "$function"
-        printf "            `echo "$function" | sed -e 's/./ /g'`  %s %s)\n" "$returntype" "$function"
+	printf "            %s  %s %s)\n" "$(echo "$function" | sed -e 's/./ /g')" "$returntype" "$function"
 	printf "{\n"
 	printf "  gdbarch->%s = %s;\n" "$function" "$function"
 	printf "}\n"