* shlib-versions [USE_IN_LIBIO] (.*-.*-gnu-gnu*): Set earliest

supported version for libc 0.2.90.libio to GLIBC_2.2.

	* Makeconfig (soversions.mk): Grok new third column in shlib-versions,
	and use it to emit new variable `map-firstversions'.
	* scripts/firstversions.awk: New file.
	* Makerules (Versions.all): Use scripts/firstversions.awk and
	the $(map-firstversions) value to generate a modified versions list
	that includes renames in "A = B" syntax for each version set earlier
	than the "earliest symbol version" named in shlib-versions.
	* scripts/versions.awk: Recognize "A = B" lines in the input to mean
	rename version set A to B in the output to the intermediate file.
	* scripts/abi-versions.awk: New file.
	* Makerules (abi-versions.h): New target, generated by that script.
	[$(versioning) = yes] (before-compile): Prepend abi-versions.h.
	* include/shlib-compat.h: New file, uses that generated header.

scripts/abi-versions.awk

@@ -0,0 +1,39 @@
+# Script to generate <abi-versions.h> header file from Versions.all list.
+# See include/shlib-compat.h comments for explanation.
+
+BEGIN {
+  print "/* This file is automatically generated by abi-versions.awk.";
+  print "   It defines symbols used by shlib-compat.h, which see.  */";
+  print "\n#ifndef _ABI_VERSIONS_H\n#define _ABI_VERSIONS_H";
+}
+
+NF == 2 && $2 == "{" {
+  thislib = $1;
+  gsub(/[^A-Za-z0-9_ 	]/, "_"); libid = $1;
+  printf "\n/* start %s */\n", thislib;
+  next;
+}
+$1 == "}" {
+  printf "/* end %s */\n", thislib;
+  next;
+}
+
+$2 == "=" {
+  new = $3;
+  gsub(/[^A-Za-z0-9_ 	]/, "_"); id = $1;
+  printf "#define ABI_%s_%s\t0\t/* earliest supported %s */\n", libid, id, new;
+  printf "#define VERSION_%s_%s\t%s\n", libid, id, new;
+  next;
+}
+
+{
+  vers = $1;
+  gsub(/[^A-Za-z0-9_ 	]/, "_"); id = $1;
+  printf "#define ABI_%s_%s\t1\t/* support %s */\n", libid, id, vers;
+  printf "#define VERSION_%s_%s\t%s\n", libid, id, vers;
+  next;
+}
+
+END {
+  print "\n#endif /* abi-versions.h */";
+}

scripts/firstversions.awk

@@ -0,0 +1,27 @@
+# Script to preprocess Versions.all lists based on "earliest version"
+# specifications in the shlib-versions file.
+
+NF == 3 && $2 == ":" { firstversion[$1] = $3; next }
+
+NF == 2 && $2 == "{" { thislib = $1; print; next }
+
+$1 == "}" {
+  if (firstversion[thislib]) {
+    # We haven't seen the stated version, but have produced
+    # others pointing to it, so we synthesize it now.
+    printf "  %s\n", firstversion[thislib];
+  }
+  print;
+  next;
+}
+
+{
+  if (! firstversion[thislib])
+    print;
+  else if ($1 == firstversion[thislib]) {
+    print;
+    firstversion[thislib] = 0;
+  }
+  else
+    print $1, "=", firstversion[thislib];
+}

scripts/versions.awk

@@ -16,7 +16,10 @@ BEGIN {
       libs[$1] = 1;
       curlib = $1;
       while (getline < defsfile && ! /^}/) {
-	versions[$1] = 1;
+        if ($2 == "=")
+	  renamed[$1] = $3;
+	else
+	  versions[$1] = 1;
       }
     }
   }
@@ -33,6 +36,7 @@ BEGIN {
 
 # This matches the beginning of the version information for a new library.
 /^[a-zA-Z0-9_.]+/ {
+  delete renamed;
   actlib = $1;
   if (!libs[$1]) {
     printf("no versions defined for %s\n", $1) > "/dev/stderr";
@@ -43,11 +47,14 @@ BEGIN {
 
 # This matches the beginning of a new version for the current library.
 /^  [A-Za-z_]/ {
-  actver = $1;
-  if (!versions[$1]) {
+  if (renamed[$1])
+    actver = renamed[$1];
+  else if (!versions[$1]) {
     printf("version %s not defined\n", $1) > "/dev/stderr";
     exit 1;
   }
+  else
+    actver = $1;
   next;
 }