[gcc r13-5326] C-SKY: Fix wrong sysroot suffix when disable multilib.

[gcc r13-5326] C-SKY: Fix wrong sysroot suffix when disable multilib.

[qu]

https://gcc.gnu.org/g:4d518ed1c0edbfff5208e09616f98ea412b55c52

commit r13-5326-g4d518ed1c0edbfff5208e09616f98ea412b55c52
Author: Xianmiao Qu <cooper.qu@linux.alibaba.com>
Date:   Wed Jan 25 00:14:46 2023 +0800

    C-SKY: Fix wrong sysroot suffix when disable multilib.
    
    The SYSROOT_SUFFIX_SPEC works even when multilib is disabled.
    So when build no-multilib glibc toolchain and the options are
    not same as MULTILIB_DEFAULTS, the sysroot will specify wrong
    because the libc will not be installed as such.
    This bug causes glibc regression test error:
      https://sourceware.org/pipermail/libc-testresults/2023q1/010706.html
    The error is:
      /scratch/jmyers/glibc-bot/install/compilers/csky-linux-gnuabiv2/csky-glibc-linux-gnuabiv2/bin/ld: cannot find -lc: No such file or directory
    
    gcc/
            * config.gcc(csky-*-linux*): Define CSKY_ENABLE_MULTILIB
            and only include 'csky/t-csky-linux' when enable multilib.
            * config/csky/csky-linux-elf.h(SYSROOT_SUFFIX_SPEC): Don't
            define it when disable multilib.

Diff:
---
 gcc/config.gcc                   | 7 ++++++-
 gcc/config/csky/csky-linux-elf.h | 3 +++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/gcc/config.gcc b/gcc/config.gcc
index d828223c16d..89f56047cfe 100644
--- a/gcc/config.gcc
+++ b/gcc/config.gcc
@@ -1642,7 +1642,12 @@ csky-*-*)
 		;;
 	    csky-*-linux*)
 		tm_file="elfos.h gnu-user.h linux.h glibc-stdint.h ${tm_file} csky/csky-linux-elf.h"
-		tmake_file="${tmake_file} csky/t-csky csky/t-csky-linux"
+		tmake_file="${tmake_file} csky/t-csky"
+
+		if test "x${enable_multilib}" = xyes ; then
+		    tm_defines="$tm_defines CSKY_ENABLE_MULTILIB"
+		    tmake_file="${tmake_file} csky/t-csky-linux"
+		fi
 
 		case ${target} in
 		    csky-*-linux-gnu*)
diff --git a/gcc/config/csky/csky-linux-elf.h b/gcc/config/csky/csky-linux-elf.h
index 3f67af64c15..117c2a12c74 100644
--- a/gcc/config/csky/csky-linux-elf.h
+++ b/gcc/config/csky/csky-linux-elf.h
@@ -65,6 +65,8 @@
 
 #define GLIBC_DYNAMIC_LINKER "/lib/ld-linux-cskyv2%{mfloat-abi=hard:-hf}%{mbig-endian:-be}.so.1"
 
+#ifdef CSKY_ENABLE_MULTILIB
+#undef SYSROOT_SUFFIX_SPEC
 #define SYSROOT_SUFFIX_SPEC					\
   "%{mbig-endian:/big}"						\
   "%{mcpu=ck807*:/ck807}"					\
@@ -72,6 +74,7 @@
   "%{mcpu=ck800*:/ck800}"					\
   "%{mfloat-abi=softfp:/soft-fp}"				\
   "%{mfloat-abi=hard:/hard-fp}"
+#endif
 
 #define LINUX_TARGET_LINK_SPEC	"%{h*} %{version:-v}		\
    %{b}								\