[PATCH v1 2/8] gcc: Add dynamic linker path for loongarch64 native toolchain build

[Vincent Li <vincent.mc.li@gmail.com>]

When building GCC natively on loongarch64 as part of the toolchain
bootstrap, the generated spec file incorrectly uses the default system
library path "/lib" for the dynamic linker. This causes the glibc build
to fail during validation because the compiled test program requests
the system runtime linker at /lib/ld-linux-loongarch-lp64d.so.1 instead
of the toolchain-specific path /tools_loongarch64/lib/.

The ABI_GRLEN_SPEC macro in gcc/config/loongarch/gnu-user.h defines
the dynamic linker path pattern. During the initial toolchain bootstrap
stage (PASS=1 with TOOLCHAIN=1), this needs to reference $(TOOLS_DIR)/lib
where the bootstrap runtime linker is installed, rather than the system
/lib path which may not yet have a compatible runtime linker.

Add a conditional sed substitution for loongarch64 builds that replaces
'"/lib" ABI_GRLEN_SPEC' with '"$(TOOLS_DIR)/lib" ABI_GRLEN_SPEC' in
gnu-user.h. This ensures GCC generates the correct dynamic linker path
for the bootstrap environment.

Without this change, the glibc build validation fails with:
  readelf -l dummy | grep "Requesting program interpreter: /tools_loongarch64"
  make: *** [glibc:131: /usr/src/ipfire-2.x/log_loongarch64/glibc-2.43-tools] Error 1

Assisted-by: DeepSeek-V4-Flash
Signed-off-by: Vincent Li <Vincent Li <vincent.mc.li@gmail.com>
---
 lfs/gcc | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lfs/gcc b/lfs/gcc
index c3a8da602..6645b2e03 100644
--- a/lfs/gcc
+++ b/lfs/gcc
@@ -229,6 +229,10 @@ ifeq "$(TOOLCHAIN)" "1"
 	cd $(DIR_APP) && tar xfa $(DIR_DL)/mpc-$(MPC_VER).tar.gz
 	cd $(DIR_APP) && mv -v mpc-$(MPC_VER) mpc
 
+ifeq "$(BUILD_ARCH)" "loongarch64"
+	sed -i '/ABI_GRLEN_SPEC/s@"/lib" ABI_GRLEN_SPEC@"$(TOOLS_DIR)/lib" ABI_GRLEN_SPEC@g' $(DIR_APP)/gcc/config/loongarch/gnu-user.h
+endif
+
 	for file in $$(find $(DIR_APP)/gcc/config -name linux64.h -o -name linux.h \
 			-o -name sysv4.h -o -name linux-eabi.h -o -name linux-elf.h -o -name aarch64-linux.h); do \
 		echo "Processing $${file}..."; \
-- 
2.38.1