varasm.c (output_constant): Add new parameter merge_strings.

varasm.c (output_constant): Add new parameter merge_strings.

2018-10-04  Bernd Edlinger  <bernd.edlinger@hotmail.de>

        * varasm.c (output_constant): Add new parameter merge_strings.
        Make strings properly zero terminated in merge string sections.
        (mergeable_string_section): Don't fail if the last char is non-zero.
        (assemble_variable_contents): Handle merge string sections.
        (assemble_variable): Likewise.
        (assemble_constant_contents): Likewise.
        (output_constant_def_contents): Likewise.
        (output_constructor_array_range,
        output_constructor_regular_field): Adjust call to output_constant.
        (output_object_block): Adjust call to assemble_constant_contents
        and assemble_variable_contents.

testsuie:
2018-10-04  Bernd Edlinger  <bernd.edlinger@hotmail.de>

        * gnat.dg/string_merge1.adb: New test.
        * gnat.dg/string_merge2.adb: New test.
        * gcc.dg/merge-all-constants-1.c: Adjust test.
        * gcc.dg/merge-all-constants-2.c: New test.

From-SVN: r264850