* Ensure that when building gcc, libstdc++ is linked against the

libgcc of the gcc being built, not the gcc building it.
* Only include a directory in the rpath of an executable/library if it
  is actually used.  Before, the `/lib' directory of every build input
  was added to the rpath, causing many unnecessary retained
  dependencies.  For instance, Perl has a `/lib' directory, but most
  applications whose build process uses Perl don't actually link
  against Perl.  (Also added a test for this.)
* After building glibc, remove glibcbug, to prevent a retained
  dependency on gcc.
* Add a newline after `building X' in GNU Make.

svn path=/nixpkgs/trunk/; revision=911

pkgs/development/compilers/gcc/builder.sh

@@ -40,21 +40,38 @@ postConfigure() {
     if test "$noSysDirs" = "1"; then
         # Patch some of the makefiles to force linking against our own
         # glibc.
-        . $NIX_GCC/nix-support/add-flags # add glibc/gcc flags
-        extraflags="-Wl,-s $NIX_CFLAGS_COMPILE $NIX_CFLAGS_LINK"
-        for i in $NIX_LDFLAGS; do
-            extraflags="$extraflags -Wl,$i"
-        done
+        if test -e $NIX_GCC/nix-support/orig-glibc; then
+            glibc=$(cat $NIX_GCC/nix-support/orig-glibc)
+            # Ugh.  Copied from gcc-wrapper/builder.sh.  We can't just
+            # source in $NIX_GCC/nix-support/add-flags, since that
+            # would cause *this* GCC to be linked against the
+            # *previous* GCC.  Need some more modularity there.
+            extraFlags="-Wl,-s -B$glibc/lib -isystem $glibc/include \
+                -L$glibc/lib -Wl,-dynamic-linker -Wl,$glibc/lib/ld-linux.so.2"
+
+            # Oh, what a hack.  I should be shot for this.
+            # In stage 1, we should link against the previous GCC, but
+            # not afterwards.  Otherwise we retain a dependency.
+            # However, ld-wrapper, which adds the linker flags for the
+            # previous GCC, is also used in stage 2/3.  We can prevent
+            # it from adding them by NIX_GLIBC_FLAGS_SET, but then
+            # gcc-wrapper will also not add them, thereby causing
+            # stage 1 to fail.  So we use a trick to only set the
+            # flags in gcc-wrapper.
+            hook=$(pwd)/ld-wrapper-hook
+            echo "NIX_GLIBC_FLAGS_SET=1" > $hook
+            export NIX_LD_WRAPPER_START_HOOK=$hook
+        fi
 
         mf=Makefile
         sed \
-            -e "s^FLAGS_FOR_TARGET =\(.*\)^FLAGS_FOR_TARGET = \1 $extraflags^" \
+            -e "s^FLAGS_FOR_TARGET =\(.*\)^FLAGS_FOR_TARGET = \1 $extraFlags^" \
             < $mf > $mf.tmp
         mv $mf.tmp $mf
 
         mf=gcc/Makefile
         sed \
-            -e "s^X_CFLAGS =\(.*\)^X_CFLAGS = \1 $extraflags^" \
+            -e "s^X_CFLAGS =\(.*\)^X_CFLAGS = \1 $extraFlags^" \
             < $mf > $mf.tmp
         mv $mf.tmp $mf