PR gdb/14704:

* gdb_bfd.c (gdb_bfd_ref): Set BFD_DECOMPRESS.
	(zlib_decompress_section): Remove.
	(gdb_bfd_map_section): Only check for compressed section
	in mmap case.  Use bfd_get_full_section_contents.
	* osabi.c (check_note): Add 'sectsize' argument.  Read
	section data.
	(generic_elf_osabi_sniff_abi_tag_sections): Don't read
	section data.  Update for check_note change.
	* xcoffread.c (xcoff_initial_scan): Use
	bfd_get_full_section_contents.
	* py-auto-load.c (auto_load_section_scripts): Use
	bfd_get_full_section_contents.
	* contrib/cc-with-tweaks.sh: Add -Z option.
testsuite
	* gdb.base/comprdebug.exp: New file.

gdb/contrib/cc-with-tweaks.sh

@@ -36,6 +36,7 @@
 # (More documentation is to come.)
 
 # ARGS determine what is done.  They can be:
+# -Z invoke objcopy --compress-debug-sections
 # -z compress using dwz
 # -m compress using dwz -m
 # -i make an index
@@ -74,9 +75,11 @@ want_index=false
 want_dwz=false
 want_multi=false
 want_dwp=false
+want_objcopy_compress=false
 
 while [ $# -gt 0 ]; do
     case "$1" in
+	-Z) want_objcopy_compress=true ;;
 	-z) want_dwz=true ;;
 	-i) want_index=true ;;
 	-m) want_multi=true ;;
@@ -138,6 +141,12 @@ then
     exit 1
 fi
 
+if [ "$want_objcopy_compress" = true ]; then
+    $OBJCOPY --compress-debug-sections "$output_file"
+    rc=$?
+    [ $rc != 0 ] && exit $rc
+fi
+
 if [ "$want_index" = true ]; then
     $GDB --batch-silent -nx -ex "set auto-load no" -ex "file $output_file" -ex "save gdb-index $output_dir"
     rc=$?