add --enable-default-compressed-debug-sections-algorithm configure option

ChangeLog:

	* configure.ac: Add --enable-default-compressed-debug-sections-algorithm.
	* configure: Regenerate.

gas/ChangeLog:

	* NEWS: Document the new option.
	* as.c (flag_compress_debug): Set default algorithm based
	on the configure option.
	* configure.ac: Add --enable-default-compressed-debug-sections-algorithm.
	* configure: Regenerate.
	* config.in: Likewise.

ld/ChangeLog:

	* NEWS: Document the new option.
	* configure.ac: Add --enable-default-compressed-debug-sections-algorithm.
	* configure: Regenerate.
	* config.in: Likewise.
	* ldmain.c: Set default algorithm based
	on the configure option.

configure

@@ -804,6 +804,7 @@ enable_gold
 enable_ld
 enable_gprofng
 enable_compressed_debug_sections
+enable_default_compressed_debug_sections_algorithm
 enable_year2038
 enable_libquadmath
 enable_libquadmath_support
@@ -1543,6 +1544,9 @@ Optional Features:
   --enable-compressed-debug-sections={all,gas,gold,ld,none}
                           Enable compressed debug sections for gas, gold or ld
                           by default
+  --enable-default-compressed-debug-sections-algorithm={zlib,zstd}
+                          Default compression algorithm for
+                          --enable-compressed-debug-sections.
   --enable-year2038       enable support for timestamps past the year 2038
   --disable-libquadmath   do not build libquadmath directory
   --disable-libquadmath-support
@@ -3148,6 +3152,15 @@ else
 fi
 
 
+# Select default compression algorithm.
+# Check whether --enable-default_compressed_debug_sections_algorithm was given.
+if test "${enable_default_compressed_debug_sections_algorithm+set}" = set; then :
+  enableval=$enable_default_compressed_debug_sections_algorithm;
+else
+  default_compressed_debug_sections_algorithm=
+fi
+
+
 # Configure extra directories which are host specific
 
 case "${host}" in