[openwrt/openwrt] tools/elfutils: do not directly link gnulib to libelf

[LEDE Commits]

robimarko pushed a commit to openwrt/openwrt.git, branch main:
https://git.openwrt.org/5f47ccc0ea596248fdb458b933ef8a406f574f8a

commit 5f47ccc0ea596248fdb458b933ef8a406f574f8a
Author: Michael Pratt <mcpratt at pm.me>
AuthorDate: Wed May 1 17:47:26 2024 -0400

    tools/elfutils: do not directly link gnulib to libelf
    
    The compiled library resulting from importing gnulib has been
    linked to libelf in order to easily cover other link dependencies.
    However, this is not appropriate for linking libelf to other programs
    as it bloats the resulting libelf library, and may result in
    multiple defintions of symbols based on whether or not
    certain modules from gnulib are included while elfutils
    already has it's own definition of a function.
    
    This is not a problem while building elfutils, because gnulib has
    it's own way of creating function aliases and special declarations
    that allow the linker to ignore the original function definitions,
    however, when libelf is used to link to something else,
    this results in an error at link time.
    
    The gnulib manual recommended linking the libraries directly,
    but those who have written it may not have considered how this
    can affect the ability to link that library in other builds,
    they likely assume the build targets would not be a dependency.
    
    Fix this by removing the linking between gnulib and libelf
    and instead overriding Make variables in order to add linking
    between gnulib and each of the binaries provided by elfutils,
    using Make functions to avoid applying it to other subdirectories.
    
    The function tdestroy() would still be missing on macOS,
    but the existence of the gnulib tsearch object having been built
    is an indicator of whether or not it is needed
    because it is only built conditionally by gnulib,
    so include linking that object only when it exists.
    
    Block the unnecessary replacement of some functions by gnulib
    so that future linking with libelf doesn't require
    the associated gnulib "rpl" prefixed functions.
    These replacements are very strict in order to correct
    minor bugs that don't have a real impact in almost all cases
    or new standards requirements that are not yet in effect or used.
    
    Tested-by: Georgi Valkov <gvalkov at gmail.com> # macOS
    Signed-off-by: Michael Pratt <mcpratt at pm.me>
    Link: https://github.com/openwrt/openwrt/pull/15368
    Signed-off-by: Robert Marko <robimarko at gmail.com>
---
 tools/elfutils/Makefile                      | 6 ++++++
 tools/elfutils/patches/100-portability.patch | 2 +-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/tools/elfutils/Makefile b/tools/elfutils/Makefile
index b66d064e2b..39e7f80b4a 100644
--- a/tools/elfutils/Makefile
+++ b/tools/elfutils/Makefile
@@ -53,8 +53,14 @@ PKG_GNULIB_MODS = \
 
 include $(INCLUDE_DIR)/host-build.mk
 
+export $(PKG_GNULIB_BASE)=$(HOST_BUILD_DIR)/$(PKG_GNULIB_BASE)/$(PKG_GNULIB_BASE).la
+export $(PKG_GNULIB_BASE)_tsearch=$(HOST_BUILD_DIR)/$(PKG_GNULIB_BASE)/$(PKG_GNULIB_BASE)_la-tsearch.lo
+
 HOST_MAKE_FLAGS += \
 	AM_LDFLAGS='$$$$(STACK_USAGE_NO_ERROR)' \
+	LIBS+='$$$$(if $$$$(findstring $(lastword $(PKG_SUBDIRS)),$$$$(subdir)), $$$$($(PKG_GNULIB_BASE)))' \
+	LIBS+='$$$$(wildcard $$$$($(PKG_GNULIB_BASE)_tsearch))' \
+	REPLACE_FCNTL=0 REPLACE_FREE=0 REPLACE_FSTAT=0 REPLACE_OPEN=0 \
 	bin_PROGRAMS='$(PKG_PROGRAMS)' EXEEXT=
 
 ifeq ($(HOST_OS),Darwin)
diff --git a/tools/elfutils/patches/100-portability.patch b/tools/elfutils/patches/100-portability.patch
index 980b117f21..09ee8daf1f 100644
--- a/tools/elfutils/patches/100-portability.patch
+++ b/tools/elfutils/patches/100-portability.patch
@@ -198,7 +198,7 @@
  pkginclude_HEADERS = elf-knowledge.h
  
 -libelf_a_SOURCES = elf_version.c elf_hash.c elf_error.c elf_fill.c \
-+libelf_la_LIBADD = ../libgnu/libgnu.la ../lib/libeu.la -lz $(zstd_LIBS) -lpthread
++libelf_la_LIBADD = ../lib/libeu.la -lz $(zstd_LIBS) -lpthread
 +libelf_la_SOURCES = elf_version.c elf_hash.c elf_error.c \
  		   elf_begin.c elf_next.c elf_rand.c elf_end.c elf_kind.c \
  		   gelf_getclass.c elf_getbase.c elf_getident.c \