[gcc r15-11318] libstdc++: Fix up bits/std.cc symlink installation

[Jakub Jelinek]

https://gcc.gnu.org/g:cd73c738b2cf1b0a42a52e0838c06b24f0f514df

commit r15-11318-gcd73c738b2cf1b0a42a52e0838c06b24f0f514df
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Thu Jun 25 11:06:37 2026 +0200

    libstdc++: Fix up bits/std.cc symlink installation
    
    >       * src/c++23/Makefile.am (libstdc++.modules.json): Rewrite
    >       without abspath make function.
    >       (stamp-modules-bits): Likewise.
    >       * src/c++23/Makefile.in: Rebuilt.
    
    This change broke various module tests (and got backported even to 15 :( ).
    I'm using objdir as a subdirectory of the gcc tree, so ../configure ...
    
    > @@ -57,7 +57,9 @@ std.compat.cc: std.compat.cc.in std-clib.cc.in
    >  # Also put the interface units in the build-includes bits directory.
    >  stamp-modules-bits: $(includebits_DATA)
    >       @-mkdir -p $(top_builddir)/include/bits
    > -     -cd $(top_builddir)/include/bits && $(LN_S) $(abspath $?) . 2>/dev/null
    > +     -for f in $(includebits_DATA); do \
    > +       $(LN_S) $(abs_srcdir)/$$f $(top_builddir)/include/bits; \
    > +     done 2>/dev/null
    >       @$(STAMP) $@
    >
    >  all-local: stamp-module-manifest stamp-modules-bits
    
    Before this change, the
    /home/jakub/src/gcc/obj38/x86_64-pc-linux-gnu/libstdc++-v3/include/bits
    std.cc symlink used to point to
    /home/jakub/src/gcc/obj38/x86_64-pc-linux-gnu/libstdc++-v3/src/c++23/std.cc
    Now it points to
    /home/jakub/src/gcc/obj40/x86_64-pc-linux-g~-v3/../../../libstdc++-v3/src/c++23/std.cc
    which doesn't exist, the source directory only has std.cc.in file from which
    the std.cc file is generated in the build directory.
    
    The following patch fixes it by using abs_builddir instead of abs_srcdir.
    
    Fixes up
    -FAIL: g++.dg/modules/compile-std1.C -std=c++29 (test for excess errors)
    -FAIL: g++.dg/modules/compile-std1.C -std=c++29 module-cmi std (gcm.cache/std.gcm)
    -FAIL: g++.dg/modules/compile-std1.C -std=c++29 module-cmi std.compat (gcm.cache/std.compat.gcm)
    -FAIL: g++.dg/plugin/std-module-exports-c++20.C -fplugin=./std_module_exports_plugin.so (test for excess errors)
    -FAIL: g++.dg/plugin/std-module-exports-c++23.C -fplugin=./std_module_exports_plugin.so (test for excess errors)
    -FAIL: g++.dg/plugin/std-module-exports-c++26.C -fplugin=./std_module_exports_plugin.so (test for excess errors)
    
    2026-06-25  Jakub Jelinek  <jakub@redhat.com>
    
            * src/c++23/Makefile.am (stamp-modules-bits): Use abs_builddir instead
            of abs_srcdir.
            * src/c++23/Makefile.in: Regenerate.
    
    Reviewed-by: Jonathan Wakely <jwakely@redhat.com>
    (cherry picked from commit 9274edef95ab1b74b82f4a9cf14baa9004e03c0d)

Diff:
---
 libstdc++-v3/src/c++23/Makefile.am | 2 +-
 libstdc++-v3/src/c++23/Makefile.in | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/libstdc++-v3/src/c++23/Makefile.am b/libstdc++-v3/src/c++23/Makefile.am
index bd7c9f65907e..0a1a9d7b1535 100644
--- a/libstdc++-v3/src/c++23/Makefile.am
+++ b/libstdc++-v3/src/c++23/Makefile.am
@@ -55,7 +55,7 @@ std.compat.cc: std.compat.cc.in std-clib.cc.in
 stamp-modules-bits: $(includebits_DATA)
 	@-mkdir -p $(top_builddir)/include/bits
 	-for f in $(includebits_DATA); do \
-	  $(LN_S) $(abs_srcdir)/$$f $(top_builddir)/include/bits; \
+	  $(LN_S) $(abs_builddir)/$$f $(top_builddir)/include/bits; \
 	done 2>/dev/null
 	@$(STAMP) $@
 
diff --git a/libstdc++-v3/src/c++23/Makefile.in b/libstdc++-v3/src/c++23/Makefile.in
index bd603fd1adfd..dc4feb701f9e 100644
--- a/libstdc++-v3/src/c++23/Makefile.in
+++ b/libstdc++-v3/src/c++23/Makefile.in
@@ -848,7 +848,7 @@ std.compat.cc: std.compat.cc.in std-clib.cc.in
 stamp-modules-bits: $(includebits_DATA)
 	@-mkdir -p $(top_builddir)/include/bits
 	-for f in $(includebits_DATA); do \
-	  $(LN_S) $(abs_srcdir)/$$f $(top_builddir)/include/bits; \
+	  $(LN_S) $(abs_builddir)/$$f $(top_builddir)/include/bits; \
 	done 2>/dev/null
 	@$(STAMP) $@