[PATCH v2 1/4] C-SKY: Use an autoconf template to produce `preconfigure'

["Maciej W. Rozycki" <macro@embecosm.com>]

Avoid fiddling with autoconf internals and use AC_DEFINE_UNQUOTED to 
define macros in the configuration headers rather than handcoding an 
equivalent shell sequence with the use of the `as_echo' undocumented 
variable.

Switch to using AC_MSG_ERROR rather than `echo' and `exit' directly for 
error handling.  Owing to the lack of any kind of error annotation it 
makes it difficult to spot the message in the flood in a parallel build 
and neither it is logged in `config.log'.
---
New change in v2.
---
 sysdeps/csky/preconfigure    |   27 +++++++++++++--------
 sysdeps/csky/preconfigure.ac |   55 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 72 insertions(+), 10 deletions(-)

glibc-csky-preconfigure-as-fn-error.diff
Index: glibc/sysdeps/csky/preconfigure
===================================================================
--- glibc.orig/sysdeps/csky/preconfigure
+++ glibc/sysdeps/csky/preconfigure
@@ -1,3 +1,6 @@
+# This file is generated from configure.ac by Autoconf.  DO NOT EDIT!
+# Local preconfigure fragment for sysdeps/csky
+
 case "$machine" in
 csky*)
     abi=`$CC $CFLAGS $CPPFLAGS -E -dM -xc /dev/null |
@@ -11,16 +14,14 @@ csky*)
 
     case "$abi" in
     1)
-        echo "glibc does not support abiv1 yet" >&2
-        exit 1
-        ;;
+	as_fn_error 1 "glibc does not support abiv1 yet" "$LINENO" 5
+	;;
     2)
-        machine=abiv2
-        ;;
+	machine=abiv2
+	;;
     *)
-        echo "Unknown abi" >&2
-        exit 1
-        ;;
+	as_fn_error 1 "Unknown abi" "$LINENO" 5
+	;;
     esac
 
     # __CSKY_HARD_FLOAT_ABI__ was added on gcc 11 to specify whether
@@ -48,7 +49,13 @@ csky*)
     base_machine=csky
     machine=csky/$machine
 
-    $as_echo "#define CSKYABI $abi" >>confdefs.h
-    $as_echo "#define CSKY_HARD_FLOAT $with_fp_cond" >>confdefs.h
+    cat >>confdefs.h <<_ACEOF
+#define CSKYABI $abi
+_ACEOF
+
+    cat >>confdefs.h <<_ACEOF
+#define CSKY_HARD_FLOAT $with_fp_cond
+_ACEOF
+
     ;;
 esac
Index: glibc/sysdeps/csky/preconfigure.ac
===================================================================
--- /dev/null
+++ glibc/sysdeps/csky/preconfigure.ac
@@ -0,0 +1,55 @@
+GLIBC_PROVIDES[]dnl See aclocal.m4 in the top level source directory.
+# Local preconfigure fragment for sysdeps/csky
+
+case "$machine" in
+csky*)
+    abi=`$CC $CFLAGS $CPPFLAGS -E -dM -xc /dev/null |
+      sed -n 's/^#define __CSKYABI__ \(.*\)/\1/p'`
+    hard_float=`$CC $CFLAGS $CPPFLAGS -E -dM -xc /dev/null |
+      sed -n 's/^#define __CSKY_HARD_FLOAT__ \(.*\)/\1/p'`
+    hard_float_sf=`$CC $CFLAGS $CPPFLAGS -E -dM -xc /dev/null |
+      sed -n 's/^#define __CSKY_HARD_FLOAT_FPU_SF__ \(.*\)/\1/p'`
+    hard_float_abi=`$CC $CFLAGS $CPPFLAGS -E -dM -xc /dev/null |
+      sed -n 's/^#define __CSKY_HARD_FLOAT_ABI__ \(.*\)/\1/p'`
+
+    case "$abi" in
+    1)
+	AC_MSG_ERROR([glibc does not support abiv1 yet], [1])
+	;;
+    2)
+	machine=abiv2
+	;;
+    *)
+	AC_MSG_ERROR([Unknown abi], [1])
+	;;
+    esac
+
+    # __CSKY_HARD_FLOAT_ABI__ was added on gcc 11 to specify whether
+    # -mfloat-abi=hard is set.  On older gcc, the float ABI is defined solely
+    # with __CSKY_HARD_FLOAT__.  If __CSKY_HARD_FLOAT__ is set, it can be
+    # either a hard-float ABI (gcc older than 11, or gcc11 -mfloat-abi=hard
+    # (__CSKY_HARD_FLOAT_ABI__ is set) or -mfloat-abi=softfp
+    # (__CSKY_HARD_FLOAT_ABI__ is not set). To be compatible with older gcc,
+    # use __CSKY_HARD_FLOAT_FPU_SF__ identify if -mfloat-abi is supported,
+    # because it is added to gcc at the same time as -mfloat-abi.
+    if test -n "$hard_float"; then
+	if test -z "$hard_float_sf"; then
+	    with_fp_cond=1
+	else
+	    if test -n "$hard_float_abi"; then
+		with_fp_cond=1
+	    else
+		with_fp_cond=0
+	    fi
+	fi
+    else
+	with_fp_cond=0
+    fi
+
+    base_machine=csky
+    machine=csky/$machine
+
+    AC_DEFINE_UNQUOTED([CSKYABI], [$abi])
+    AC_DEFINE_UNQUOTED([CSKY_HARD_FLOAT], [$with_fp_cond])
+    ;;
+esac