[patch, avr] Fix PR30417: Wrap -Tdata into %{!Tdata:...}.

[Georg-Johann Lay]

This patch allows to specify -Tdata and -Ttext on the command line for MCUs 
where the specs file sets these options.  For -mmcu=atmega88 for example, the 
respective specs reads:

*link_data_start:
        -Tdata 0x800100
and the patch changes this to

*link_data_start:
        %{!Tdata:-Tdata 0x800100}

Same for *link_text_start and -Ttext.

Ok for trunk and backport?

Johann


        PR target/30417
        * config/avr/gen-avr-mmcu-specs.c (print_mcu):
        [*link_data_start]: Wrap -Tdata into %{!Tdata:...}.
        [*link_text_start]: Wrap -Ttext into %{!Ttext:...}.

Index: config/avr/gen-avr-mmcu-specs.c
===================================================================
--- config/avr/gen-avr-mmcu-specs.c	(revision 237587)
+++ config/avr/gen-avr-mmcu-specs.c	(working copy)
@@ -242,12 +242,13 @@ bool is_arch = NULL == mcu->macro;
       fprintf (f, "*link_data_start:\n");
       if (mcu->data_section_start
           != arch->default_data_section_start)
-        fprintf (f, "\t-Tdata 0x%lX", 0x800000UL + mcu->data_section_start);
+        fprintf (f, "\t%%{!Tdata:-Tdata 0x%lX}",
+                 0x800000UL + mcu->data_section_start);
       fprintf (f, "\n\n");
 
       fprintf (f, "*link_text_start:\n");
       if (mcu->text_section_start != 0x0)
-        fprintf (f, "\t-Ttext 0x%lX", 0UL + mcu->text_section_start);
+        fprintf (f, "\t%%{!Ttext:-Ttext 0x%lX}", 0UL + mcu->text_section_start);
       fprintf (f, "\n\n");
     }