BaseTools GCC: move AutoGen.obj contents to .text section

All AutoGen.obj files consist of global GUID definitions, fixed
and patchable PCDs and other data that is essentially read-only at
runtime but has not been declared as such for various reasons.

By moving these contents to .text we achieve two things:
- global GUIDs and other data items which must be constant for correct
  program operation can no longer be modified, for instance, when
  running a DXE_RUNTIME_MODULE binary under the OS with the Properties
  Table feature for memory protection enabled;
- the .data section becomes smaller, and may be dropped completely for
  many XIP modules, which reduces wasted FV space if the PE/COFF section
  alignment is large.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Tested-by: Liming Gao <liming.gao@intel.com>
Tested-by: Leif Lindholm <leif.lindholm@linaro.org>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18137 6f19259b-4bc3-4df7-8a09-765794883524

BaseTools/Scripts/GccBase.lds

@@ -29,6 +29,13 @@ SECTIONS {
     *(.text .text.* .stub .gnu.linkonce.t.*)
     *(.rodata .rodata.* .gnu.linkonce.r.*)
     *(.got .got.*)
+
+    /*
+     * The contents of AutoGen.c files are constant from the POV of the program,
+     * but most of its contents end up in .data or .bss by default since few of
+     * the variable definitions that get emitted are declared as CONST.
+     */
+    *:AutoGen.obj(.data .data.* .bss .bss.*)
   }
 
   /*